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Technical Heat Treatment Guidelines and Operating Conditions Manual

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8th Revision

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This document will be updated as required. For further information or clarification, please contact the Canadian Food Inspection Agency (CFIA).

Amendment record

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Distribution

  1. Directive mail list (regions, areas, Plant Heath Risk Assessment)
  2. Provincial Government, Industry (via regions)
  3. National Industry Organizations (determined by author)
  4. Candidate Service providers
  5. Forest Products Advisory Committee
  6. CFIA recognized Heat Treatment Evaluators

Subject

The Technical Heat Treatment Guidelines and Operating Conditions Manual is a supplementary document designed to accompany the CFIA policy directive, D-13-01, Canadian Heat Treated Wood Products Certification Program (HT Program). This manual prescribes heat treatment chamber operating conditions and defines the technical requirements to participate in the HT Program.

Introduction

Generic phytosanitary heat treatment schedules for all softwood (coniferous) tree species and all hardwood (deciduous) species grown in Canada are contained within,

These generic heat treatment schedules (options A, B, C, D, E, F, G, H and 1), are science-based and approved by the CFIA and may be used by all treatment facilities registered under D-13-01. Each generic schedule contains sufficient safeguarding measures to ensure that all wood products treated according to the schedule will meet the phytosanitary standard, a minimum wood core temperature of 56°C for a minimum of 30 minutes.

The appropriate heat treatment schedule for wood packaging will be based on the maximum individual lumber thickness (vertical or horizontal) or the combination of wood members in close contact and perpendicular to air flow. The combined thickness shall not exceed the wood thickness for the applied schedule. The treatment of such products may require additional technical review by CFIA, a recognized heat treatment evaluator or CFIA service providers to ensure proper chamber loading procedures are developed and that chamber air flow will be sufficient to heat treat wood packaging products.

Treatment facilities may choose to develop specific or use existing kiln-specific treatment schedules to increase the efficiency of their kiln and to decrease the minimum heat treatment time, to treat wood species or dimensional lumber not covered by the generic treatment schedules, or to enable the use of a kiln, or heat treatment chamber, not meeting the prescriptive minimum criteria of the generic treatment schedules. Each specific schedule must be verified by a recognized heat treatment evaluator to ensure the kiln will consistently treat lumber and wood products to meet the phytosanitary standard. The recognized heat treatment evaluator will recommend the specific schedule or process for approval to the CFIA and if acceptable the treatment facility will add the specific schedule to their Quality Management System Manual (herein referred to as "the manual").

A list of recognized heat treatment evaluators is maintained on the CFIA Forestry website at www.inspection.gc.ca. All costs for the development of specific schedules are the responsibility of the treatment facility.

Any deviation to the operating conditions set out in this document not approved and documented by a CFIA recognized Heat Treatment Evaluator will be referred to the Canadian Forest Products Advisory Committee for review, approval and documented in a "Request for Decision". Any modifications to prescribed procedures must be described and included in the manual.

1.0 Scope

This manual is intended for use by facilities registered under the HT program (D-13-01), recognized heat treatment evaluators, the Canadian Lumber Standards Accreditation Board (CLSAB) and their Accredited Agencies, CFIA Approved Third Party Auditors, and CFIA inspection staff.

This manual outlines technical information for the export of certified wood products heat treated in accordance with foreign import requirements and International Standards for Phytosanitary Measures (ISPM 15).

2.0 References

3.0 Definitions, abbreviations and acronyms

Kiln
Consists of 1 or more chambers designed to provide and control the environmental conditions of heat, humidity and air circulation to enable the heat treatment and/or drying of wood
Batch kiln
A kiln designed for a batch process in which the kiln is completely loaded and charged with lumber or wood packaging in 1 operation, and the product being treated may remain stationary during the process
Bi-directional continuous kiln
A dual path kiln having multiple zones with at least 2 lumber charge paths adapted to continuously move lumber through the kiln in opposite directions
Kiln length
The kiln length is defined as distance between ends of the kiln
Kiln end
The kiln ends are parallel to the air flow in the kiln
Kiln side
The kiln sides are perpendicular to the air flow in the kiln
Kiln mid-third section

The mid-third section of a kiln is relative to the kiln length

  • Appendix A provides diagrams illustrating the foregoing definition for kiln length
  • Appendix B provides batch kiln layout diagrams illustrating the foregoing definitions for options A, B, B-1-wom, C, D, E, F, F-1 and G

The following definitions pertain to bi-directional continuous kilns:

Entering section
Entering sections of a continuous kiln without controlled artificial heating and no doors
Exiting section
Exiting sections of a continuous kiln without controlled artificial heating and no doors
Ramp-up zone (RUZ)
Is the zone within a continuous kiln where the minimum heat treatment run starts
Ramp-up zone length (RUZL)
The ramp-up zone length is the distance from the beginning of the mid-third of the entering section of each track to the beginning of the heat treatment zone (HTZ)
Heat treatment zone (HTZ)
Zone(s) within the main heating section of a continuous kiln where the heat treatment will be monitored based upon temperature sensor location(s)
Heat treatment zone length (HTZL)

Temperature sensors will be used to determine the heat treatment zone length (HTZL) according to each specific option as described in the following sections

  • Appendix C provides bi-directional continuous kilns layout illustrating the foregoing definitions for options A, B and D
  • Appendix D provides bi-directional continuous kiln layout diagrams illustrating the foregoing definitions for options A, B, B-1-wom and D

Definitions for terms used in the present document can be found in the Plant Health Glossary of Terms.

4.0 Approved generic phytosanitary heat treatment schedules for wood products and heat treatment chamber operating conditions

The generic phytosanitary heat treatment schedules (options A, B, C, D, E, F, G, and H) and heat treatment chamber operating conditions are for use by heat treatment facilities registered under CFIA Policy Directive D-13-01. These schedules are designed to meet the phytosanitary standard and can be used to heat treat the following softwood and hardwood tree species.

Generic phytosanitary heat treatment (56°C throughout the profile for 30 minutes) schedules options A, B, C and D

These schedules apply to:

Generic phytosanitary heat treatment (56°C throughout the profile for 30 minutes) schedules options E, F and G

These schedules apply to:

Generic phytosanitary heat treatment (71°C throughout the profile for 1200 minutes) schedules option H

These schedules apply to:

4.1 Mandatory general heat treatment chamber operating conditions

To use a heat treatment option the heat treatment chamber and facility must meet both the general conditions prescribed below along with the specific heat treatment requirements specified with each option. All general conditions and specific heat treatment requirements must be documented in the manual.

4.1.1 Adequate air flow occurs throughout all zones of the chamber. A zone is an area of 5 m long by 2.5 m high. Air velocity must be measured on the exit side of the load in all applicable directions with a minimum velocity of 0.5 metres/second (100 feet/minute).

4.1.2 Lumber must be stacked on stickers of no less than 9.5 mm (⅜ inch) in thickness and in a manner to provide adequate air flow. Wood packaging or other wood products must be piled in a manner to provide good air circulation through and over all wide surfaces of individual boards.

Note: the orientation of the wood packaging relative to the airflow is critical in determining the applicable product thickness to each treatment option. Refer to Appendix E for instruction on how to assess wood packaging product thickness relative to treatment option selection.

4.1.3 All equipment must be in proper working conditions and the manual must specify the practices that are undertaken by the facility to ensure the normal operation of all equipment including heat sensors.

4.1.4 The dry and wet bulb measuring system must accurately measure the temperature within ± 2.5°C (4.5°F). The verification of the measuring system will be required for options A through G and H-1 on an annual basis. This requirement may be removed where the temperature exceeds the requirement for options A, B, D, E, and F by at least 5°C and by at least 10°C for option C, G, and H-1. For option H-2, the dry bulb measuring system must accurately measure the temperature within ± 1.0°C (1.8°F). The verification of the measuring system for option H-2 will be required twice a year by an independent party.

4.1.5 To ensure that facilities are prepared to deal with non-conforming equipment, the facility must specify procedures for dealing with failure or deficiencies in equipment operation including heat sensors, fans, etc.

4.1.6 If a facility is not in operation for a period of 6 months or longer, the facility must specify steps used in ensuring that the equipment is in normal operating condition before beginning treatments.

4.1.7 The RUZ, RUZL, HTZ, and HTZL for each track for facilities operating bi-directional continuous kilns must be determined (see Section 3.0).

4.1.8 Where the option requires moisture reduction, the verification method will be defined in the manual.

4.1.9 Any deviation to the operating conditions set out in this document not approved and documented by a CFIA recognized Heat Treatment Evaluator will be referred to the Canadian Forest Products Advisory Committee for review, approval and documented in a "Request for Decision". Any modifications to prescribed procedures must be described and included in the manual.

4.2 Option A, A-1, A-2, A-3, A-4, A-5, A-6: heat treatment schedule with or without moisture reduction

This option can be used by a facility to heat treat wood during the thermal treatment (HT) or kiln drying (KD) process.

4.2.1 Specific heat treatment chamber operating conditions

The temperatures must be recorded at a minimum of every 30 minutes.

Air flow should occur in each of 2 opposite directions within the treatment chamber for half of the time specified at the wet bulb temperature equal to or exceeding the "wet bulb temperature continuous run time" (see tables for each option).

4.2.1.1 Batch kilns

Dry bulb temperature sensors can be located on either side of the heat treatment chamber. Sensors must be spaced not more than 7 metres (24 feet) apart, perpendicularly to the air flow with 1 located no more than 2.5 m (8.5 feet) from each end of the treatment chamber. The number of dry bulb sensors required will depend on the length of the individual kiln and the above sensor placement scale. The dry bulb temperature must exceed the wet bulb temperature during the heat treatment to ensure the uniformity of the heat treatment chamber conditions.

At least 1 wet bulb temperature sensor, either measuring wet bulb temperature or providing data to determine the wet bulb temperature must be located within the mid third section of the treatment chamber, on any 1 side.

Appendix B provides a diagram illustrating the minimum layout requirements for option A – batch kiln.

For wood greater than 57 mm (2¼ inches) in thickness, the initial wood core temperature of wood to be treated must be equal to or higher than 15°C (59° F) in order to use generic schedules of options A. If not, 1 of the 2 following methods to determine the pre-schedule time to be added at the heat treatment schedules must be used as follows:

method 1 – The treatment chamber must be pre-heated until the wood core temperature of at least 1 piece of lumber of the thickest nominal size reaches 15°C (59°F). At least 1 sensor (or equivalent process) must verify and record the wood core temperature.

or

method 2 – If no wood core temperature monitoring is conducted, the pre-schedule time must be determined by 1 of the following means:

  1. measure and record initial wood core temperature by thermometer such as thermocouple

    or

  2. assume wood temperature is equal to the previous night's, outside, low temperature Please note that where the wood core temperature is below 15°C (59°F) the temperature adjustment will need to be added to the minimum continuous heat treatment run time.

For option A adjust as follows:

For options A-1 to A-6 refer to method 1.

4.2.1.2 Bi-directional continuous kilns (applies only to option A)

The following temperature bulb placements are available to a registered facility operating a bi-directional continuous kiln.

1 wet bulb

3 wet bulbs

4 wet bulbs

Appendix D provides a diagram illustrating the minimum layout requirements for option A and B – bi-directional continuous kiln.

4.2.2 Option A: generic phytosanitary heat treatment schedule

Lumber thickness Minimum heat treatment run time Wet bulb temperature continuous run time ≥ 60°C/≥ 140°F Minimum final wet-bulb temperature
(°C) / (°F)
Up to 57 mm (2¼ inches) 6 hrs, 26 minutes 2 hrs, 03 minutes 63 /145
Up to 83 mm (3¼ inches) 7 hrs, 20 minutes 3 hrs, 20 minutes 66 /151
Up to 108 mm (4¼ inches) 10 hrs, 57 minutes 6 hrs, 34 minutes 67 /153

4.2.3 Option A-1: generic phytosanitary heat treatment schedule

Lumber thickness Minimum heat treatment run time Wet bulb temperature continuous run time ≥ 70°C/≥ 158°F Minimum final wet-bulb temperature
(°C) / (°F)
Up to 127 mm (5 inches) 9 hrs, 38 minutes 5 hrs, 08 minutes 70 / 158
Up to 152 mm (6 inches) 11 hrs, 16 minutes 6 hrs, 46 minutes 70 / 158
Up to 178 mm (7 inches) 13 hrs, 14 minutes 8 hrs, 44 minutes 70 / 158
Up to 203 mm (8 inches) 15 hrs, 37 minutes 11 hrs, 07 minutes 70 / 158
Up to 228 mm (9 inches) 18 hrs, 25 minutes 13 hrs, 55 minutes 70 / 158
Up to 254 mm (10 inches) 21 hrs, 44 minutes 17 hrs, 14 minutes 70 / 158
Up to 279 mm (11 inches) 25 hrs, 36 minutes 21 hrs, 06 minutes 70 / 158
Up to 305 mm (12 inches) 30 hrs, 04 minutes 25 hrs, 34 minutes 70 / 158

4.2.4 Option A-2: generic phytosanitary heat treatment schedule

Lumber thickness Minimum heat treatment run time Wet bulb temperature continuous run time ≥ 69°C/≥ 156°F Minimum final wet-bulb temperature
(°C) / (°F)
Up to 127 mm (5 inches) 11 hrs, 10 minutes 6 hrs, 40 minutes 69 / 156
Up to 152 mm (6 inches) 12 hrs, 16 minutes 8 hrs, 46 minutes 69 / 156
Up to 178 mm (7 inches) 15 hrs, 49 minutes 11 hrs, 19 minutes 69 / 156
Up to 203 mm (8 inches) 18 hrs, 52 minutes 14 hrs, 22 minutes 69 / 156
Up to 228 mm (9 inches) 22 hrs, 29 minutes 17 hrs, 59 minutes 69 / 156
Up to 254 mm (10 inches) 26 hrs, 44 minutes 22 hrs, 14 minutes 69 / 156
Up to 279 mm (11 inches) 31 hrs, 41 minutes 27 hrs, 11 minutes 69 / 156
Up to 305 mm (12 inches) 37 hrs, 24 minutes 32 hrs, 54 minutes 69 / 156

4.2.5 Option A-3: generic phytosanitary heat treatment schedule

Lumber thickness Minimum heat treatment run time Wet bulb temperature continuous run time ≥ 68°C/≥ 154°F Minimum final wet-bulb temperature
(°C) / (°F)
Up to 127 mm (5 inches) 12 hrs, 18 minutes 7 hrs, 48 minutes 68 / 154
Up to 152 mm (6 inches) 14 hrs, 45 minutes 10 hrs, 15 minutes 68 / 154
Up to 178 mm (7 inches) 17 hrs, 44 minutes 13 hrs, 14 minutes 68 / 154
Up to 203 mm (8 inches) 21 hrs, 17 minutes 16 hrs, 47 minutes 68 / 154
Up to 228 mm (9 inches) 25 hrs, 30 minutes 21 hrs, 00 minutes 68 / 154
Up to 254 mm (10 inches) 30 hrs, 26 minutes 25 hrs, 56 minutes 68 / 154
Up to 279 mm (11 inches) 36 hrs, 11 minutes 31 hrs, 41 minutes 68 / 154
Up to 305 mm (12 inches) 42 hrs, 49 minutes 38 hrs, 19 minutes 68 / 154

4.2.6 Option A-4: generic phytosanitary heat treatment schedule

Lumber thickness Minimum heat treatment run time Wet bulb temperature continuous run time ≥ 67°C/≥ 152°F Minimum final wet-bulb temperature
(°C) / (°F)
Up to 127 mm (5 inches) 13 hrs, 14 minutes 8 hrs, 44 minutes 67 / 152
Up to 152 mm (6 inches) 15 hrs, 59 minutes 11 hrs, 29 minutes 67 / 152
Up to 178 mm (7 inches) 19 hrs, 18 minutes 14 hrs, 48 minutes 67 / 152
Up to 203 mm (8 inches) 23 hrs, 16 minutes 18 hrs, 46 minutes 67 / 152
Up to 228 mm (9 inches) 27 hrs, 58 minutes 23 hrs, 28 minutes 67 / 152
Up to 254 mm (10 inches) 33 hrs, 29 minutes 28 hrs, 59 minutes 67 / 152
Up to 279 mm (11 inches) 39 hrs, 53 minutes 35 hrs, 23 minutes 67 / 152
Up to 305 mm (12 inches) 47 hrs, 17 minutes 42 hrs, 47 minutes 67 / 152

4.2.7 Option A-5: generic phytosanitary heat treatment schedule

Lumber thickness Minimum heat treatment run time Wet bulb temperature continuous run time ≥ 66°C/≥ 150°F Minimum final wet-bulb temperature
(°C) / (°F)
Up to 127 mm (5 inches) 14 hrs, 03 minutes 9 hrs, 33 minutes 66 / 150
Up to 152 mm (6 inches) 17 hrs, 02 minutes 12 hrs, 32 minutes 66 / 150
Up to 178 mm (7 inches) 20 hrs, 39 minutes 16 hrs, 09 minutes 66 / 150
Up to 203 mm (8 inches) 24 hrs, 59 minutes 20 hrs, 29 minutes 66 / 150
Up to 228 mm (9 inches) 30 hrs, 07 minutes 25 hrs, 37 minutes 66 / 150
Up to 254 mm (10 inches) 36 hrs, 07 minutes 31 hrs, 37 minutes 66 / 150
Up to 279 mm (11 inches) 43 hrs, 05 minutes 38 hrs, 35 minutes 66 / 150
Up to 305 mm (12 inches) 51 hrs, 09 minutes 46 hrs, 39 minutes 66 / 150

4.2.8 Option A-6: generic phytosanitary heat treatment schedule

Lumber thickness Minimum heat treatment run time Wet bulb temperature continuous run time ≥ 64°C/≥ 148°F Minimum final wet-bulb temperature
(°C) / (°F)
Up to 127 mm (5 inches) 14 hrs, 46 minutes 10 hrs, 16 minutes 64 / 148
Up to 152 mm (6 inches) 17 hrs, 59 minutes 13 hrs, 29 minutes 64 / 148
Up to 178 mm (7 inches) 21 hrs, 52 minutes 17 hrs, 22 minutes 64 / 148
Up to 203 mm (8 inches) 26 hrs, 31 minutes 22 hrs, 01 minute 64 / 148
Up to 228 mm (9 inches) 32 hrs, 01 minute 27 hrs, 31 minutes 64 / 148
Up to 254 mm (10 inches) 38 hrs, 28 minutes 33 hrs, 58 minutes 64 / 148
Up to 279 mm (11 inches) 45 hrs, 57 minutes 41 hrs, 27 minutes 64 / 148
Up to 305 mm (12 inches) 54 hrs, 36 minutes 50 hrs, 06 minutes 64 / 148

4.3 Option B: heat treatment schedule with moisture reduction

This option can be used by a facility to heat treat wood during the thermal treatment (HT) or kiln drying (KD) process.

4.3.1 Option B: specific heat treatment chamber operating conditions

Temperatures must be recorded at a minimum of every 30 minutes.

Air flow should occur in each of 2 opposite directions within the treatment chamber for approximately half of the time specified at the "wet bulb temperature continuous run time" temperature specific to thickness for each option.

4.3.1.1 Batch kilns

At least 1 wet bulb temperature sensor either measuring wet bulb temperature, or providing data to determine the wet bulb temperature must be located within the mid-third section of the heat treatment

chamber, on any 1 side.

The heat treatment chamber must be equipped with at least 1 dry-bulb temperature sensor. If the air entering/air exiting plenum is divided into 3 equal length segments, the temperature sensor(s) must be located as follows. At least 1 dry-bulb temperature sensor will be located within the mid-third segment of the kiln (on either side). If this condition is met, the location of other sensors is not restricted. In lieu of a dry-bulb temperature sensor within the mid-third of the kiln, the kiln can be operated with 2 (or more) dry-bulb temperature sensors with at least 1 sensor located in each of the 2 segments located at opposite ends of the kiln (on either side). The dry-bulb temperature must exceed the wet-bulb temperature during the heat treatment to ensure the uniformity of the heat treatment chamber conditions.

Appendix B provides a diagram illustrating the minimum layout requirements for option B – batch kiln.

For wood greater than 57 mm (2¼ inches) in thickness the initial wood core temperature of wood to be treated must be equal to or higher than 15°C (59°F). If not, 1 of the 2 following methods to determine the pre-schedule time to be added at the heat treatment schedules must be used as follows:

method 1 – The treatment chamber must be pre-heated until the wood core temperature of at least 1 piece of lumber of the thickest nominal size reaches 15°C (59°F). At least 1 sensor (or equivalent process) must verify and record the wood core temperature.

or

method 2 – If no wood core temperature monitoring is conducted the pre-schedule time must be determined by 1 of the following means:

  1. measure and record initial wood core temperature by thermometer such as thermocouple

    or

  2. assume wood temperature is equal to the previous night's, outside, low temperature. Please note that where the wood core temperature is below 15°C (59°F) the following temperature adjustment will need to be added to the minimum continuous heat treatment run time.

For option B adjust as follows:

For options B-1 to B-6 refer to method 1.

4.3.1.2 Bi-directional continuous kilns – Applies only to option B

Refer to option A.

4.3.2 Option B: generic phytosanitary heat treatment schedule

Lumber thickness Minimum heat treatment run time Wet bulb temperature continuous run time ≥ 60°C /≥ 140°F Minimum final wet-bulb temperature
(°C) / (°F)
Up to 57 mm (2¼ inches) 8 hrs, 29 minutes 4 hrs, 06 minutes 63 / 145
Up to 83 mm (3¼ inches) 10 hrs, 40 minutes 6 hrs, 40 minutes 66 / 151
Up to 108 mm (4¼ inches) 17 hrs, 31 minutes 13 hrs, 08 minutes 67 /153

4.3.3 Option B-1: generic phytosanitary heat treatment schedule

Lumber thickness Minimum heat treatment run time Wet bulb temperature continuous run time ≥ 70°C /≥ 158°F Minimum final wet-bulb temperature
(°C) / (°F)
Up to 127 mm (5 inches) 14 hrs, 46 minutes 10 hrs, 16 minutes 70 / 158
Up to 152 mm (6 inches) 18 hrs, 02 minutes 13 hrs, 32 minutes 70 / 158
Up to 178 mm (7 inches) 21 hrs, 58 minutes 17 hrs, 28 minutes 70 / 158
Up to 203 mm (8 inches) 26 hrs, 44 minutes 22 hrs, 14 minutes 70 / 158
Up to 228 mm (9 inches) 32 hrs, 20 minutes 27 hrs, 50 minutes 70 / 158
Up to 254 mm (10 inches) 38 hrs, 58 minutes 34 hrs, 28 minutes 70 / 158
Up to 279 mm (11 inches) 46 hrs, 42 minutes 42 hrs, 12 minutes 70 / 158
Up to 305 mm (12 inches) 55 hrs, 38 minutes 51 hrs, 08 minutes 70 / 158

4.3.4 Option B-2: generic phytosanitary heat treatment schedule

Lumber thickness Minimum heat treatment run time Wet bulb temperature continuous run time ≥ 69°C /≥ 156°F Minimum final wet-bulb temperature
(°C) / (°F)
Up to 127 mm (5 inches) 17 hrs, 50 minutes 13 hrs, 20 minutes 69 / 156
Up to 152 mm (6 inches) 22 hrs, 02 minutes 17 hrs, 32 minutes 69 / 156
Up to 178 mm (7 inches) 27 hrs, 08 minutes 22 hrs, 38 minutes 69 / 156
Up to 203 mm (8 inches) 33 hrs, 14 minutes 28 hrs, 44 minutes 69 / 156
Up to 228 mm (9 inches) 40 hrs, 28 minutes 35 hrs, 58 minutes 69 / 156
Up to 254 mm (10 inches) 48 hrs, 58 minutes 44 hrs, 28 minutes 69 / 156
Up to 279 mm (11 inches) 58 hrs, 52 minutes 54 hrs, 22 minutes 69 / 156
Up to 305 mm (12 inches) 70 hrs, 18 minutes 65 hrs, 48 minutes 69 / 156

4.3.5 Options B-3: generic phytosanitary heat treatment schedule

Lumber thickness Minimum heat treatment run time Wet bulb temperature continuous run time ≥ 68°C /≥ 154°F Minimum final wet-bulb temperature
(°C) / (°F)
Up to 127 mm (5 inches) 20 hrs, 06 minutes 15 hrs, 36 minutes 68 / 154
Up to 152 mm (6 inches) 25 hrs, 00 minutes 20 hrs, 30 minutes 68 / 154
Up to 178 mm (7 inches) 30 hrs, 58 minutes 26 hrs, 28 minutes 68 / 154
Up to 203 mm (8 inches) 38 hrs, 04 minutes 33 hrs, 34 minutes 68 / 154
Up to 228 mm (9 inches) 46 hrs, 30 minutes 42 hrs, 00 minutes 68 / 154
Up to 254 mm (10 inches) 56 hrs, 22 minutes 51 hrs, 52 minutes 68 / 154
Up to 279 mm (11 inches) 67 hrs, 52 minutes 63 hrs, 22 minutes 68 / 154
Up to 305 mm (12 inches) 81 hrs, 08 minutes 76 hrs, 38 minutes 68 / 154

4.3.6 Options B-4: generic phytosanitary heat treatment schedule

Lumber thickness Minimum heat treatment run time Wet bulb temperature continuous run time ≥ 67°C c/≥ 152°F Minimum final wet-bulb temperature
(°C) / (°F)
Up to 127 mm (5 inches) 21 hrs, 58 minutes 17 hrs, 28 minutes 67 / 152
Up to 152 mm (6 inches) 27 hrs, 28 minutes 22 hrs, 58 minutes 67 / 152
Up to 178 mm (7 inches) 34 hrs, 06 minutes 29 hrs, 36 minutes 67 / 152
Up to 203 mm (8 inches) 42 hrs, 02 minutes 37 hrs, 32 minutes 67 / 152
Up to 228 mm (9 inches) 51 hrs, 26 minutes 46 hrs, 56 minutes 67 / 152
Up to 254 mm (10 inches) 62 hrs, 28 minutes 57 hrs, 58 minutes 67 / 152
Up to 279 mm (11 inches) 75 hrs, 16 minutes 70 hrs, 46 minutes 67 / 152
Up to 305 mm (12 inches) 90 hrs, 04 minutes 85 hrs, 34 minutes 67 / 152

4.3.7 Options B-5: generic phytosanitary heat treatment schedule

Lumber thickness Minimum heat treatment run time Wet bulb temperature continuous run time ≥ 66°C /≥ 150°F Minimum final wet-bulb temperature
(°C) / (°F)
Up to 127 mm (5 inches) 23 hrs, 36 minutes 19 hrs, 06 minutes 66 / 150
Up to 152 mm (6 inches) 29 hrs, 34 minutes 25 hrs, 04 minutes 66 / 150
Up to 178 mm (7 inches) 36 hrs, 48 minutes 32 hrs, 18 minutes 66 / 150
Up to 203 mm (8 inches) 45 hrs, 28 minutes 40 hrs, 58 minutes 66 / 150
Up to 228 mm (9 inches) 55 hrs, 44 minutes 51 hrs, 14 minutes 66 / 150
Up to 254 mm (10 inches) 67 hrs, 44 minutes 63 hrs, 14 minutes 66 / 150
Up to 279 mm (11 inches) 81 hrs, 40 minutes 77 hrs, 10 minutes 66 / 150
Up to 305 mm (12 inches) 97 hrs, 48 minutes 93 hrs, 18 minutes 66 / 150

4.3.8 Options B-6: generic phytosanitary heat treatment schedule

Lumber thickness Minimum heat treatment run time Wet bulb temperature continuous run time ≥ 64°C /≥ 148°F Minimum final wet-bulb temperature
(°C) / (°F)
Up to 127 mm (5 inches) 25 hrs, 02 minutes 20 hrs, 32 minutes 64 / 148
Up to 152 mm (6 inches) 31 hrs, 28 minutes 26 hrs, 58 minutes 64 / 148
Up to 178 mm (7 inches) 39 hrs, 14 minutes 34 hrs, 44 minutes 64 / 148
Up to 203 mm (8 inches) 48 hrs, 32 minutes 44 hrs, 02 minutes 64 / 148
Up to 228 mm (9 inches) 59 hrs, 32 minutes 55 hrs, 02 minutes 64 / 148
Up to 254 mm (10 inches) 72 hrs, 26 minutes 67 hrs, 56 minutes 64 / 148
Up to 279 mm (11 inches) 87 hrs, 24 minutes 82 hrs, 54 minutes 64 / 148
Up to 305 mm (12 inches) 104 hrs, 42 minutes 93 hrs, 18 minutes 64 / 148

4.4 Option B-1-wom: heat treatment schedule without moisture reduction (wom)

Moisture reduction is not required to use this option.

4.4.1 Option B-1-wom: specific heat treatment chamber operating conditions

Temperatures must be recorded at a minimum of every 30 minutes.

Air flow should occur in each of 2 opposite directions within the treatment chamber for half of the time specified at the wet bulb temperature equal to or exceeding the "wet bulb temperature continuous Run time" (see tables for each option).

4.4.2 Batch kilns

At least 1 wet bulb temperature sensor either measuring wet bulb temperature, or providing data to determine the wet bulb temperature must be located within the mid-third section of the heat treatment chamber, on any 1 side.

At least 3 dry bulb temperature sensors must be located on either side of the heat treatment chamber. Sensors must be spaced approximately at equal distance apart perpendicular to the air flow. 1 sensor must be located at each end of the treatment chamber. These sensors should be placed closest to the end of the treatment chamber (approximately < 5 m (16.5 feet)). For chambers equal to or less than 17 metres (56 feet) in length (in the direction perpendicular to air flow) the number of dry bulb sensors can be reduced to 2 dry bulb sensors with the above placement criteria. The dry bulb temperature must exceed the wet bulb temperature during heat treatment to ensure the uniformity of the heat treatment chamber conditions.

Appendix B provides a diagram illustrating the minimum layout requirements for option B-1 – batch kiln.

For wood greater than 57 mm (2¼ inches) in thickness the initial wood core temperature of wood to be treated must be equal to or higher than 15°C (59°F). If not, 1 of the 2 following methods to determine the pre-schedule time to be added at the heat treatment schedules must be used as follows:

method 1 – The treatment chamber must be pre-heated until the wood core temperature of at least 1 piece of lumber of the thickest nominal size reaches 15°C (59°F). At least 1 sensor (or equivalent process) must verify and record the wood core temperature

or

method 2 – If no wood core temperature monitoring is conducted the pre-schedule time must be determined by 1 of the following means:

  1. measure and record initial wood core temperature by thermometer such as thermocouple

    or

  2. assume wood temperature is equal to the previous night's, outside, low temperature. Please note that where the wood core temperature is below 15°C (59°F) the following temperature adjustment will need to be added to the minimum continuous heat treatment run time

For option B-1 adjust as follows:

For options B-2-wom to B-7-wom refer to method 1.

4.4.3 Bi-directional continuous kilns – Applies only to option B-1

Refer to option A.

4.4.4 Option B-1-wom: generic phytosanitary heat treatment schedule

Lumber thickness Minimum heat treatment run time Wet bulb temperature continuous run time ≥ 60°C /≥ 140°F Minimum final wet-bulb temperature
(°C) / (°F)
Up to 57 mm (2¼ inches) 8 hrs, 29 minutes 4 hrs, 06 minutes 63 / 145
Up to 83 mm (3¼ inches) 10 hrs, 40 minutes 6 hrs, 40 minutes 66 / 151
Up to 108 mm (4¼ inches) 17 hrs, 31 minutes 13 hrs, 08 minutes 67 /153

4.4.5 Option B-2-wom: generic phytosanitary heat treatment schedule

Lumber thickness Minimum heat treatment run time Wet bulb temperature continuous run time ≥ 70°C /≥ 158°F Minimum final wet-bulb temperature
(°C) / (°F)
Up to 127 mm (5 inches) 14 hrs, 46 minutes 10 hrs, 16 minutes 70 / 158
Up to 152 mm (6 inches) 18 hrs, 02 minutes 13 hrs, 32 minutes 70 / 158
Up to 178 mm (7 inches) 21 hrs, 58 minutes 17 hrs, 28 minutes 70 / 158
Up to 203 mm (8 inches) 26 hrs, 44 minutes 22 hrs, 14 minutes 70 / 158
Up to 228 mm (9 inches) 32 hrs, 20 minutes 27 hrs, 50 minutes 70 / 158
Up to 254 mm (10 inches) 38 hrs, 58 minutes 34 hrs, 28 minutes 70 / 158
Up to 279 mm (11 inches) 46 hrs, 42 minutes 42 hrs, 12 minutes 70 / 158
Up to 305 mm (12 inches) 55 hrs, 38 minutes 51 hrs, 08 minutes 70 / 158

4.4.6 Option B-3-wom: generic phytosanitary heat treatment schedule

Lumber thickness Minimum heat treatment run time Wet bulb temperature continuous run time ≥ 69°C /≥ 156°F Minimum final wet-bulb temperature
(°C) / (°F)
Up to 127 mm (5 inches) 17 hrs, 50 minutes 13 hrs, 20 minutes 69 / 156
Up to 152 mm (6 inches) 22 hrs, 02 minutes 17 hrs, 32 minutes 69 / 156
Up to 178 mm (7 inches) 27 hrs, 08 minutes 22 hrs, 38 minutes 69 / 156
Up to 203 mm (8 inches) 33 hrs, 14 minutes 28 hrs, 44 minutes 69 / 156
Up to 228 mm (9 inches) 40 hrs, 28 minutes 35 hrs, 58 minutes 69 / 156
Up to 254 mm (10 inches) 48 hrs, 58 minutes 44 hrs, 28 minutes 69 / 156
Up to 279 mm (11 inches) 58 hrs, 52 minutes 54 hrs, 22 minutes 69 / 156
Up to 305 mm (12 inches) 70 hrs, 18 minutes 65 hrs, 48 minutes 69 / 156

4.4.7 Options B-4-wom: generic Phytosanitary Heat Treatment Schedule

Lumber thickness Minimum heat treatment run time Wet bulb temperature continuous run time ≥ 68°C /≥ 154°F Minimum final wet-bulb temperature
(°C) / (°F)
Up to 127 mm (5 inches) 20 hrs, 06 minutes 15 hrs, 36 minutes 68 / 154
Up to 152 mm (6 inches) 25 hrs, 00 minutes 20 hrs, 30 minutes 68 / 154
Up to 178 mm (7 inches) 30 hrs, 58 minutes 26 hrs, 28 minutes 68 / 154
Up to 203 mm (8 inches) 38 hrs, 04 minutes 33 hrs, 34 minutes 68 / 154
Up to 228 mm (9 inches) 46 hrs, 30 minutes 42 hrs, 00 minutes 68 / 154
Up to 254 mm (10 inches) 56 hrs, 22 minutes 51 hrs, 52 minutes 68 / 154
Up to 279 mm (11 inches) 67 hrs, 52 minutes 63 hrs, 22 minutes 68 / 154
Up to 305 mm (12 inches) 81 hrs, 08 minutes 76 hrs, 38 minutes 68 / 154

4.4.8 Options B-5-wom: generic phytosanitary heat treatment schedule

Lumber thickness Minimum heat treatment run time Wet bulb temperature continuous run time ≥ 67°C /≥ 152°F Minimum final wet-bulb temperature
(°C) / (°F)
Up to 127 mm (5 inches) 21 hrs, 58 minutes 17 hrs, 28 minutes 67 / 152
Up to 152 mm (6 inches) 27 hrs, 28 minutes 22 hrs, 58 minutes 67 / 152
Up to 178 mm (7 inches) 34 hrs, 06 minutes 29 hrs, 36 minutes 67 / 152
Up to 203 mm (8 inches) 42 hrs, 02 minutes 37 hrs, 32 minutes 67 / 152
Up to 228 mm (9 inches) 51 hrs, 26 minutes 46 hrs, 56 minutes 67 / 152
Up to 254 mm (10 inches) 62 hrs, 28 minutes 57 hrs, 58 minutes 67 / 152
Up to 279 mm (11 inches) 75 hrs, 16 minutes 70 hrs, 46 minutes 67 / 152
Up to 305 mm (12 inches) 90 hrs, 04 minutes 85 hrs, 34 minutes 67 / 152

4.4.9 Options B-6-wom: generic phytosanitary heat treatment schedule

Lumber thickness Minimum heat treatment run time Wet bulb temperature continuous run time ≥ 66°C /≥ 150°F Minimum final wet-bulb temperature
(°C) / (°F)
Up to 127 mm (5 inches) 23 hrs, 36 minutes 19 hrs, 06 minutes 66 / 150
Up to 152 mm (6 inches) 29 hrs, 34 minutes 25 hrs, 04 minutes 66 / 150
Up to 178 mm (7 inches) 36 hrs, 48 minutes 32 hrs, 18 minutes 66 / 150
Up to 203 mm (8 inches) 45 hrs, 28 minutes 40 hrs, 58 minutes 66 / 150
Up to 228 mm (9 inches) 55 hrs, 44 minutes 51 hrs, 14 minutes 66 / 150
Up to 254 mm (10 inches) 67 hrs, 44 minutes 63 hrs, 14 minutes 66 / 150
Up to 279 mm (11 inches) 81 hrs, 40 minutes 77 hrs, 10 minutes 66 / 150
Up to 305 mm (12 inches) 97 hrs, 48 minutes 93 hrs, 18 minutes 66 / 150

4.4.10 Options B-7-wom: generic phytosanitary heat treatment schedule

Lumber thickness Minimum heat treatment run time Wet bulb temperature continuous run time ≥ 64°C /≥ 148°F Minimum final wet-bulb temperature
(°C) / (°F)
Up to 127 mm (5 inches) 25 hrs, 02 minutes 20 hrs, 32 minutes 64 / 148
Up to 152 mm (6 inches) 31 hrs, 28 minutes 26 hrs, 58 minutes 64 / 148
Up to 178 mm (7 inches) 39 hrs, 14 minutes 34 hrs, 44 minutes 64 / 148
Up to 203 mm (8 inches) 48 hrs, 32 minutes 44 hrs, 02 minutes 64 / 148
Up to 228 mm (9 inches) 59 hrs, 32 minutes 55 hrs, 02 minutes 64 / 148
Up to 254 mm (10 inches) 72 hrs, 26 minutes 67 hrs, 56 minutes 64 / 148
Up to 279 mm (11 inches) 87 hrs, 24 minutes 82 hrs, 54 minutes 64 / 148
Up to 305 mm (12 inches) 104 hrs, 42 minutes 93 hrs, 18 minutes 64 / 148

4.5 Option C: heat treatment with moisture reduction (dry bulb only)

This option can be used by a facility to heat treat wood during the thermal treatment (HT) or kiln drying (KD) process.

4.5.1 Option C: specific heat treatment chamber operating conditions

Temperatures must be recorded at a minimum of every 30 minutes.

Air flow should occur in each of 2 opposite directions within the treatment chamber for approximately half of the time specified at the dry bulb temperature equal to or exceeding 60°C.

4.5.1.1 Batch kilns

Only dry bulb measurement is required. The facility must employ the use of at least 2 dry bulb temperature sensors.

Appendix B provides a diagram illustrating the minimum layout requirements for option C – batch kiln.

4.5.1.2 Bi-directional continuous kilns

As per site specific continuous kiln specific heat treatment schedule.

4.5.2 Option C: phytosanitary heat treatment schedule

Lumber thickness Dry bulb temperature continuous run time ≥ 52°C /≥ 126°F Minimum time at the end of the treatment with the dry-bulb ≥ 60°C) / ≥ 140°F)
Up to 29 mm (1⅛ inches) 8 hrs 4 hrs
Up to 57 mm (2¼ inches) 18 hrs 6 hrs
Up to 83 mm (3¼ inches) 45 hrs 15 hrs
Up to 108 mm (4¼ inches) 72 hrs 24 hrs

Note: the "minimum time at the end of the treatment with the dry-bulb ≥ 60°C" is included in the "dry bulb temperature continuous run time ≥52°C", measured in hours.

4.6 Option D: heat treatment schedule with moisture reduction

This option can be used by a facility to heat treat wood during the HT or KD process.

4.6.1 Option D: specific heat treatment chamber operating conditions

Only dry bulb measurement is required.

The temperatures must be recorded at a minimum of every 30 minutes.

Fan reversal is not required.

4.6.1.1 Batch kilns

The facility must employ the use of at least 2 dry bulb temperature sensors.

Appendix B provides a diagram illustrating the minimum layout requirements for option D – batch kiln.

4.6.1.2 Bi-directional continuous kilns

The following temperature bulb placements are available to a registered facility operating a bi-directional continuous kiln.

4 dry-bulbs:

Appendix D provides a diagram illustrating the minimum layout requirements for option D – bi-directional continuous kiln.

4.6.2 Option D: generic phytosanitary heat treatment schedule

Lumber thickness Heat treatment continuous run time Minimum time at the end of the treatment with the dry-bulb ≥ 71°C (≥ 160°F)
Up to 29 mm (1⅛ inches) 9 hrs 3 hrs
Up to 57 mm (2¼ inches) 12 hrs 6 hrs
Up to 83 mm (3¼ inches) 22 hrs 16 hrs
Up to 108 mm (4¼ inches) 32 hrs 26 hrs
Up to 133 mm (5¼ inches) 42 hrs 36 hrs

Note: the "minimum time at the end of the treatment with the dry-bulb ≥ 71°C" is included in the "heat treatment run time", measured in hours.

4.7 Option E, E-1, E-2, E-3, E-4, E-5, E-6: hardwood heat treatment schedule with or without moisture reduction

This option can be used by a facility to heat treat wood during the HT or KD process.

This option is limited to use in batch kilns.

4.7.1 Specific heat treatment chamber operating conditions

Temperatures must be recorded at a minimum of every 30 minutes.

Air flow should occur in each of 2 opposite directions within the treatment chamber for half of the time specified at the wet bulb temperature equal to or exceeding the wet bulb temperature continuous run time (see tables for each option).

4.7.1.1 Batch kilns

Dry bulb temperature sensors can be located on either side of the heat treatment chamber. Sensors must be spaced not more than 7 metres (24 feet) apart, perpendicular to the air flow with 1 located no more than 2.5 m (8.5 feet) from each end of the treatment chamber. The number of dry bulb sensors required will depend on the length of the individual kiln and the above sensor placement scale. The dry bulb temperature must exceed the wet bulb temperature during the heat treatment to ensure the uniformity of the heat treatment chamber conditions.

At least 1 wet bulb temperature sensor, either measuring wet bulb temperature or providing data to determine the wet bulb temperature must be located within the mid third section of the treatment chamber, on any 1 side.

Appendix B provides a diagram illustrating the minimum layout requirements for option E – batch kiln.

For wood greater than 57 mm (2¼ inches) in thickness the initial wood core temperature of wood to be treated must be equal to or higher than 15°C (59°F). If not, 1 of the 2 following methods to determine the pre-schedule time to be added at the heat treatment schedules must be used as follows:

method 1 – The treatment chamber must be pre-heated until the wood core temperature of at least 1 piece of lumber of the thickest nominal size reaches 15°C (59°F). At least 1 sensor (or equivalent process) must verify and record the wood core temperature

or

method 2 – If no wood core temperature monitoring is conducted the pre-schedule time must be determined by 1 of the following means:

  1. measure and record initial wood core temperature by thermometer such as thermocouple

    or

  2. assume wood temperature is equal to the previous night's, outside, low temperature. Please note that where the wood core temperature is below 15°C (59°F) the following temperature adjustment will need to be added to the minimum continuous heat treatment run time

For option E adjust as follows:

For options E-1 to E-6 refer to method 1.

4.7.1 Option E: generic hardwood phytosanitary heat treatment schedule

Lumber thickness Minimum heat treatment run time Wet bulb temperature continuous run time ≥ 60°C /≥ 140°F Minimum final wet-bulb temperature
(°C) / (°F)
Up to 57 mm (2¼ inches) 8 hrs, 02 minutes 2 hrs, 46 minutes 63 / 145
Up to 83 mm (3¼ inches) 9 hrs, 10 minutes 4 hrs, 30 minutes 66 / 151
Up to 108 mm (4¼ inches) 13 hrs, 40 minutes 8 hrs, 52 minutes 67 / 153

4.7.2 Option E-1: generic hardwood phytosanitary heat treatment schedule

Lumber thickness Minimum heat treatment run time Wet bulb temperature continuous run time ≥ 70°C /≥ 158°F Minimum final wet-bulb temperature
(°C) / (°F)
Up to 127 mm (5 inches) 11 hrs, 26 minutes 6 hrs, 56 minutes 70 / 158
Up to 152 mm (6 inches) 13 hrs, 38 minutes 9 hrs, 08 minutes 70 / 158
Up to 178 mm (7 inches) 16 hrs, 17 minutes 11 hrs, 47 minutes 70 / 158
Up to 203 mm (8 inches) 19 hrs, 30 minutes 15 hrs, 00 minutes 70 / 158
Up to 228 mm (9 inches) 23 hrs, 17 minutes 18 hrs, 47 minutes 70 / 158
Up to 254 mm (10 inches) 27 hrs, 46 minutes 23 hrs, 16 minutes 70 / 158
Up to 279 mm (11 inches) 32 hrs, 59 minutes 28 hrs, 29 minutes 70 / 158
Up to 305 mm (12 inches) 39 hrs, 01 minute 34 hrs, 31 minutes 70 / 158

4.7.3 Option E-2: generic hardwood phytosanitary heat treatment schedule

Lumber thickness Minimum heat treatment run time Wet bulb temperature continuous run time ≥ 69°C /≥ 156°F Minimum final wet-bulb temperature
(°C) / (°F)
Up to 127 mm (5 inches) 13 hrs, 30 minutes 9 hrs, 00 minutes 69 / 156
Up to 152 mm (6 inches) 16 hrs, 20 minutes 11 hrs, 50 minutes 69 / 156
Up to 178 mm (7 inches) 19 hrs, 47 minutes 15 hrs, 17 minutes 69 / 156
Up to 203 mm (8 inches) 23 hrs, 54 minutes 19 hrs, 24 minutes 69 / 156
Up to 228 mm (9 inches) 28 hrs, 47 minutes 24 hrs, 17 minutes 69 / 156
Up to 254 mm (10 inches) 34 hrs, 31 minutes 30 hrs, 01 minute 69 / 156
Up to 279 mm (11 inches) 41 hrs, 12 minutes 36 hrs, 42 minutes 69 / 156
Up to 305 mm (12 inches) 48 hrs, 55 minutes 44 hrs, 25 minutes 69 / 156

4.7.4 Option E-3: generic hardwood phytosanitary heat treatment schedule

Lumber thickness Minimum heat treatment run time Wet bulb temperature continuous run time ≥ 68°C /≥ 154°F Minimum final wet-bulb temperature
(°C) / (°F)
Up to 127 mm (5 inches) 15 hrs, 02 minutes 10 hrs,32 minutes 68 / 154
Up to 152 mm (6 inches) 18 hrs, 20 minutes 13 hrs, 50 minutes 68 / 154
Up to 178 mm (7 inches) 22 hrs, 22 minutes 17 hrs, 52 minutes 68 / 154
Up to 203 mm (8 inches) 27 hrs, 09 minutes 22 hrs, 39 minutes 68 / 154
Up to 228 mm (9 inches) 32 hrs, 51 minutes 28 hrs, 21 minutes 68 / 154
Up to 254 mm (10 inches) 39 hrs, 31 minutes 35 hrs, 01 minute 68 / 154
Up to 279 mm (11 inches) 47 hrs, 16 minutes 42 hrs, 46 minutes 68 / 154
Up to 305 mm (12 inches) 56 hrs, 14 minutes 51 hrs, 44 minutes 68 / 154

4.7.5 Option E-4: generic hardwood phytosanitary heat treatment schedule

Lumber thickness Minimum heat treatment run time Wet bulb temperature continuous run time ≥ 67°C /≥ 152°F Minimum final wet-bulb temperature
(°C) / (°F)
Up to 127 mm (5 inches) 16 hrs, 17 minutes 11 hrs, 47 minutes 67/152
Up to 152 mm (6 inches) 20 hrs, 00 minutes 15 hrs, 30 minutes 67 / 152
Up to 178 mm (7 inches) 24 hrs, 29 minutes 19 hrs, 59 minutes 67 / 152
Up to 203 mm (8 inches) 29 hrs, 50 minutes 25 hrs, 20 minutes 67 / 152
Up to 228 mm (9 inches) 36 hrs, 11 minutes 31 hrs, 41 minutes 67 / 152
Up to 254 mm (10 inches) 43 hrs, 38 minutes 39 hrs, 08 minutes 67 / 152
Up to 279 mm (11 inches) 52 hrs, 16 minutes 47 hrs, 46 minutes 67 / 152
Up to 305 mm (12 inches) 62 hrs, 15 minutes 57 hrs, 45 minutes 67 / 152

4.7.6 Option E-5: generic hardwood phytosanitary heat treatment schedule

Lumber thickness Minimum heat treatment run time Wet bulb temperature continuous run time ≥ 66°C /≥ 150°F Minimum final wet-bulb temperature
(°C) / (°F)
Up to 127 mm (5 inches) 17 hrs, 24 minutes 12 hrs, 54 minutes 66 / 150
Up to 152 mm (6 inches) 21 hrs, 25 minutes 16 hrs, 55 minutes 66 / 150
Up to 178 mm (7 inches) 26 hrs, 18 minutes 21 hrs, 48 minutes 66 / 150
Up to 203 mm (8 inches) 32 hrs, 09 minutes 27 hrs, 39 minutes 66 / 150
Up to 228 mm (9 inches) 39 hrs, 05 minutes 34 hrs, 35 minutes 66 / 150
Up to 254 mm (10 inches) 47 hrs, 11 minutes 42 hrs, 41 minutes 66 / 150
Up to 279 mm (11 inches) 56 hrs, 35 minutes 52 hrs, 05 minutes 66 / 150
Up to 305 mm (12 inches) 67 hrs, 29 minutes 62 hrs, 59 minutes 66 / 150

4.7.7 Option E-6: generic hardwood phytosanitary heat treatment schedule

Lumber thickness Minimum heat treatment run time Wet bulb temperature continuous run time ≥ 64°C /≥ 148°F Minimum final wet-bulb temperature
(°C) / (°F)
Up to 127 mm (5 inches) 18 hrs, 22 minutes 13 hrs, 52 minutes 64 / 148
Up to 152 mm (6 inches) 22 hrs, 42 minutes 18 hrs, 12 minutes 64 / 148
Up to 178 mm (7 inches) 27 hrs, 57 minutes 23 hrs, 27 minutes 64 / 148
Up to 203 mm (8 inches) 34 hrs, 13 minutes 29 hrs, 43 minutes 64 / 148
Up to 228 mm (9 inches) 41 hrs, 39 minutes 37 hrs, 09 minutes 64 / 148
Up to 254 mm (10 inches) 50 hrs, 21 minutes 45 hrs, 51 minutes 64 / 148
Up to 279 mm (11 inches) 60 hrs, 27 minutes 55 hrs, 57 minutes 64 / 148
Up to 305 mm (12 inches) 72 hrs, 08 minutes 67 hrs, 38 minutes 64 / 148

4.8 Option F and F-1: hardwood heat treatment schedule with and without moisture reduction

This option can be used by a facility to heat treat wood during the HT or KD process.

This option is limited to use in batch kilns.

4.8.1 Option F and F-1: specific heat treatment chamber operating conditions

Temperatures must be recorded at a minimum of every 30 minutes.

Air flow should occur in each of 2 opposite directions within the treatment chamber for approximately half of the time specified at the wet bulb temperature equal to or exceeding 60°C.

4.8.1.1 Batch kilns

At least 1 wet bulb temperature sensor either measuring wet bulb temperature, or providing data to determine the wet bulb temperature must be located within the mid third of the heat treatment chamber, on any 1 side.

For wood greater than 57 mm (2¼ inches) in thickness the initial wood core temperature of wood to be treated must be equal to or higher than 15°C (59°F). If not, 1 of the 2 following methods to determine the pre-schedule time to be added at the heat treatment schedules must be as follows:

method 1 – The treatment chamber must be pre-heated until the wood core temperature of at least 1 piece of lumber of the thickest nominal size reaches 15°C (59°F). At least 1 sensor (or equivalent process) must verify and record the wood core temperature

or

method 2 – If no wood core temperature monitoring is conducted the pre-schedule time must be determined by 1 of the following means:

  1. measure and record initial wood core temperature by thermometer such as thermocouple

    or

  2. assume wood temperature is equal to the previous night's, outside, low temperature. Please note that where the wood core temperature is below 15°C (59°F) the temperature adjustment will need to be added to the minimum continuous heat treatment run time.

For option F and F-1 adjust as follows:

4.8.2 Option F: specific heat treatment chamber operating conditions with moisture reduction

The heat treatment chamber must be equipped with at least 1 dry-bulb temperature sensor. If the air entering/air exiting plenum is divided into 3 equal length segments, the temperature sensor(s) must be located as follows. At least 1 dry-bulb temperature sensor will be located within the mid-third segment of the kiln (on either side). If this condition is met, the location of other sensors is not restricted. In lieu of a dry-bulb temperature sensor within the mid-third of the kiln, the kiln can be operated with 2 (or more) dry-bulb temperature sensors with at least 1 sensor located in each of the 2 segments located at opposite ends of the kiln (on either side). The dry-bulb temperature must exceed the wet-bulb temperature during the heat treatment to ensure the uniformity of the heat treatment chamber conditions. The temperature must be recorded at a minimum of every 30 minutes.

Appendix B provides a diagram illustrating the minimum layout requirements for option F – batch kiln.

4.8.3 Option F: generic hardwood phytosanitary heat treatment schedule

Lumber thickness Minimum heat treatment run time Wet bulb temperature continuous run time ≥ 60°C /≥ 140°F Minimum final wet-bulb temperature
(°C) / (°F)
Up to 57 mm (2¼ inches) 10 hrs, 36 minutes 5 hrs, 32 minutes 63 / 145
Up to 83 mm (3¼ inches) 13 hrs, 20 minutes 9 hrs, 00 minutes 66 / 151
Up to 108 mm (4¼ inches) 21 hrs, 54 minutes 17 hrs, 44 minutes 67 / 153

4.8.4 Option F-1: specific heat treatment chamber operating conditions without moisture reduction

At least 3 dry bulbs temperature sensor must be located on either side of the heat treatment chamber. Sensors must be spaced approximately at equal distance apart perpendicularly to the air flow. 1 sensor must be located at each end of the treatment chamber. These sensors should be placed closest to the end of the treatment chamber (approximately > 5 m (16.5 feet)). For chamber equal to or less than 17 metres (56 feet) in length (in the direction perpendicular to air flow) the number of dry bulb sensors can be reduced to 2 dry bulb sensors with the above placement criteria. The dry bulb temperature must exceed the wet bulb temperature during the heat treatment to ensure the uniformity of the heat treatment chamber conditions. The temperatures must be recorded at a minimum of every 30 minutes.

Appendix B provides a diagram illustrating the minimum layout requirements for option F – batch kiln.

Option F-1: generic hardwood phytosanitary heat treatment schedule
Lumber thickness Minimum heat treatment run time Wet bulb temperature continuous run time ≥ 60°C / ≥ 140°F Minimum final wet-bulb temperature
(°C) / (°F)
Up to 57 mm (2¼ inches) 10 hrs, 36 minutes 5 hrs, 32 minutes 63 / 145
Up to 83 mm (3¼ inches) 13 hrs, 20 minutes 9 hrs, 00 minutes 66 / 151
Up to 108 mm (4¼ inches) 21 hrs, 54 minutes 17 hrs, 44 minutes 67 / 153

4.9 Option G: hardwood heat treatment schedule with moisture reduction

This option can be used by a facility to heat treat wood during the thermal treatment (HT) or kiln drying (KD) process.

This option is limited to use in batch kilns.

4.9.1 Option G: specific heat treatment chamber operating conditions

Temperatures must be recorded at a minimum of every 30 minutes.

Only dry bulb measurement is required.

4.9.1.1 Batch kilns

Air flow should alternate in each of 2 opposite directions within the treatment chamber for approximately half of the time specified at the dry bulb temperature equal to or exceeding 60°C.

This requirement may be modified where it can be technically proven, by recognized heat treatment evaluator and when others measures can compensate for deviation. Any modifications must be included in the manual and account for all the processes used to ensure that the phytosanitary standard is being met.

The facility must employ the use of at least 2 dry bulb temperature sensors.

4.9.2 Option G: generic hardwood phytosanitary heat treatment schedule

Lumber thickness Dry-bulb temperature continuous run time ≥ 52°C / ≥ 126°F Minimum time at the end of the treatment with the dry-bulb ≥ 60°C / ≥ 140°F
Up to 28 mm (1⅛ inches) 12 hrs, 00 minutes 6 hrs, 00 minutes
Up to 57 mm (2¼ inches) 27 hrs, 00 minutes 9 hrs, 00 minutes
Up to 83 mm (3¼ inches) 67 hrs, 30 minutes 22 hrs, 30 minutes
Up to 108 mm (4¼ inches) 108 hrs, 00 minutes 36 hrs, 00 minutes

4.10 Option H-1 and H-2: hardwood heat treatment schedule to 71°C throughout the profile for 1200 minutes with moisture reduction

This option can be used by a facility to heat treat wood during the HT or KD process. This option is limited to use in batch kilns.

4.10.1 Option H: specific heat treatment chamber operating conditions

The temperatures must be recorded at a minimum of every 30 minutes. Only dry bulb measurement is required. The facility must employ the use of at least 2 dry bulb temperature sensors.

4.10.2 Option H-1: hardwood heat treatment schedules to 71°C throughout the profile for 1200 minutes

Air flow should alternate in each of 2 opposite directions within the treatment chamber for approximately half of the time specified at the dry bulb temperature equal to or exceeding 75°C.

4.10.3. Option H-1: generic hardwood phytosanitary heat treatment schedule

Lumber thickness Dry-bulb temperature continuous run time ≥ 67°C / ≥ 153°F Minimum time at the end of the treatment with the dry-bulb ≥ 75°C / ≥ 167°F
Up to 28 mm (1⅛ inches) 31 hrs, 30 minutes 25 hrs, 30 minutes
Up to 57 mm (2¼ inches) 46 hrs, 30 minutes 28 hrs, 30 minutes
Up to 83 mm (3¼ inches) 87 hrs, 00 minutes 42 hrs, 00 minutes
Up to 108 mm (4¼ inches) 127 hrs, 30 minutes 55 hrs, 30 minutes

4.10.4 Option H-2: hardwood heat treatment schedules to 71°C throughout the profile for 1200 minutes (with independent verification check)

Air flow should alternate in each of 2 opposite directions within the treatment chamber for approximately half of the time specified at the dry bulb temperature equal to or exceeding 73°C.

Dry bulb measuring system must accurately measure the temperature within ± 1.0°C (1.8°F). The verification of the measuring system will be required twice a year by an independent party.

4.10.5. Option H-2: generic hardwood phytosanitary heat treatment schedule

Lumber thickness Dry-bulb temperature continuous run time ≥ 65°C / ≥ 149°F Minimum time at the end of the treatment with the dry-bulb ≥ 73°C / ≥ 163°F
Up to 28 mm (1⅛ inches) 31 hrs, 30 minutes 25 hrs, 30 minutes
Up to 57 mm (2¼ inches) 46 hrs, 30 minutes 28 hrs, 30 minutes
Up to 83 mm (3¼ inches) 87 hrs, 00 minutes 42 hrs, 00 minutes
Up to 108 mm (4¼ inches) 127 hrs, 30 minutes 55 hrs, 30 minutes

5.0 Approved generic phytosanitary heat treatment schedules for wood products dried in low temperature/dehumidification kiln operating conditions

The generic phytosanitary heat treatment schedule for wood products dried in low temperature/dehumidification kilns (option 1) are for use by heat treatment facilities registered under CFIA Policy Directive D-13-01. The schedule is designed to meet the phytosanitary standard for coniferous softwood species grown in Canada.

This option only applies to softwood (coniferous) species grown in Canada and is intended for higher value appearance grade lumber such as 1" spruce, western red cedar, eastern white pine, red pine, etc.

Option 1 – Heat treatment – Application of condition period after kiln drying lumber (dry bulb only)

This option is for low temperature and/or dehumidification kilns that kiln dry lumber. A low temperature heat treatment chamber and/or dehumidification kiln is identified as operating between approximately 43°C (110°F) and 56°C (133°F) for an extended period during the kiln drying cycle. When the operating conditions of this option are followed the material will meet the requirements of being kiln dried (KD) and heat treated (HT). The material must be kiln dried (KD) prior to the application of the condition period which enables the HT declaration.

This option only applies to softwood (coniferous) species grown in Canada and is intended for higher value appearance grade lumber such as 1" spruce, western red cedar, eastern white pine, red pine, etc.

Option 1 – Operating conditions

General:

Moisture content:

Operating temperatures:the initial kiln operating temperature as measured by the dry-bulb shall be at least 43°C (110°F).

The dry-bulb temperature of the kiln customarily remains below 56°C (133°F) during the kiln drying cycle and prior to the application of the condition period. Where the dry-bulb temperature exceeds 56°C (133°F) for extended period of time during the kiln drying cycle, option C or D shall be selected.

Prior to the application of the condition period the dry-bulb operating temperature should operate in the range of 52°C (125°F) and 56°C (133°F) for a minimum of 25 hours. When the dry-bulb operating temperature is lower than 52°C (125°F) and/or operating time is less 25 hours, the facility shall demonstrate compliance with KD-HT. When demonstration of compliance is required, the facility shall provide a record of compliance for review by the auditor.

Condition period:
Kiln to meet or exceed 60°C (140°F) for at least 1 hour after the kiln drying cycle.

Lumber thickness:
Up to 57 mm (2¼ inches).

Appendix A: diagrams illustrating batch kiln definitions

Appendix A: diagrams illustrating batch kiln definitions. Description follows.
Appendix A – Text version

Appendix A contains 2 diagrams illustrating the definitions for batch kiln given in section 3.0 for options A, B, C, D, E, F, G and H. The top diagram shows a kiln, where the side (perpendicular to air flow) is at the top, the end (parallel to air flow) on the right and kiln length (which is the distance between the ends) is represented at the bottom. There is a section in the middle of the kiln, at the bottom, showing the mid-third section (relative to kiln length). The direction of airflow (2 arrows indicate fan reversal) is represented by an arrow parallel to the end of the kiln on the right

The bottom diagram shows a kiln, where the side (perpendicular to air flow) is on the right, the end (parallel to air flow) at the top and kiln length (which is the distance between the ends) is represented on the left. There is a section in the middle of the kiln, at the middle on the left, showing the mid-third section (relative to kiln length). The direction of airflow (2 arrows indicate fan reversal) is represented by an arrow parallel to the end of the kiln at the top.

Appendix B: batch kiln layout diagrams

Appendix B: batch kiln layout diagrams. Description follows.
Appendix B – Text version

Appendix B contains diagrams illustrating the definitions for batch kiln given in section 3.0 for options A, B, B-1-wom, C, D, E, F, F-1 and G.

The first diagram illustrates the minimum requirements for option A or E and is entitled Minimum layout requirements for a batch kiln. The kiln length is 57 feet (distance between the ends) and is the same as the side length (perpendicular to air flow) and is represented by an arrow at the bottom of the image. At the top, positions of the first dry bulb is at 8.5 feet from the left and 8.5 feet is the maximum distance allowed from each end. The wet bulb is located in the mid-third of the kiln on either side, so within a 19 feet section at the middle of the kiln. The dry bulb temperature sensors must be located on at least 1 side of the heat treatment chamber with no more than 24 feet between dry bulbs. On the diagram, the 2 other dry bulbs are located at 8.5 feet and 20 feet from the right. The center of the kiln is represented with an arrow of 28.5 feet. The direction of the flow is represented by 2 vertical arrows indicating fan reversal. The maximum velocity is 0.5 m/second (100 feet/minute), the air velocity is measured on the exit side of the chamber of the load. Also see section 4.2.1.1 and 4.7 of this document.

The second diagram illustrates the minimum requirements for option B or F and is entitled Minimum layout requirements for a batch kiln with air entering/air exiting plenum is divided into 3 equal length segments. The kiln length is 57 feet (distance between the ends) and is the same as the side length (perpendicular to air flow) and is represented by an arrow at the bottom of the image. At the top, position of the first dry bulb is at 19 feet (segment) from the left, in lieu of dry bulb located in the mid-third of the kiln, 1 dry bulb is located in each the segments (19 feet each) located at opposite ends of the kiln on either side. The wet bulb is located in the mid-third of the kiln on either side, so within a 19 feet section at the middle of the kiln. There is also a dry bulb located in the mid-third of the kiln on either side. The center of the kiln is represented with an arrow of 28.5 feet. The direction of the flow is represented by 2 vertical arrows indicating fan reversal. The maximum velocity is 0.5 m/second (100 feet/minute), the air velocity is measured on the exit side of the chamber of the load. Also see section 4.3.1.1 and 4.8.2 of this document.

The third diagram illustrates the minimum requirements for option B-1-wom or F-1 and is entitled Minimum layout requirements for a batch kiln with or without moisture reduction. The kiln length is 57 feet (distance between the ends) and is the same as the side length (perpendicular to air flow) and is represented by an arrow at the bottom of the image. A the top, positions of the first dry bulb is at approximately 16.5 feet from the left. At least 3 dry bulb temperature sensors must be equally spaced and located on either side of the chamber, at approximately 16.5 feet from each end of the chamber and in the mid-third of the kiln. The wet bulb is located the mid-third of kiln on either side, so within a 19 feet section in the middle of the kiln. The center of the kiln is represented with an arrow of 28.5 feet. The direction of the flow is represented by 2 vertical arrows indicating fan reversal. The maximum velocity is 0.5 m/second (100 feet/minute), the air velocity is measured on the exit side of the chamber of the load. Also see section 4.4.2. and 4.8.4. of this document.

The fourth diagram illustrates the minimum requirements for option C or G and is entitled Minimum layout requirements for a batch kiln. At the top, positions of the 2 dry bulbs, location is not restricted, and it can be on either side of the chamber. Also, at the top, the kiln length is 57 feet (distance between the ends) is represented by an arrow. The side length (perpendicular to air flow) is at the bottom of the image. The end (parallel to air flow) is on the right. The direction of the flow is represented by 2 vertical arrows indicating fan reversal. The maximum velocity is 0.5 m/second (100 feet/minute), the air velocity is measured on the exit side of the chamber of the load. Also see section 4.5 and 4.9 of this document.

The fifth diagram illustrates the minimum requirements for option D and is entitled Minimum layout requirements for a batch kiln. At the top, positions of the 2 dry bulbs, location is not restricted, and it can be on either side of the chamber. The kiln length is 57 feet (distance between the ends) and is the same as the side length (perpendicular to air flow) and is represented by an arrow at the top of the image. The end (parallel to air flow) is on the right. The direction of the flow is represented by 2 vertical arrows indicating fan reversal. The maximum velocity is 0.5 m/second (100 feet/minute), the air velocity is measured on the exit side of the chamber of the load. Also see section 4.6 of this document.

Note: when the option prescribes the number and/or locations of bulbs and sensors based on the kiln length, the kiln length is always defined by airflow, regardless of the shape of the kiln.

Appendix C: diagrams illustrating bi-directional continuous kiln definitions

Appendix C: diagrams illustrating bi-directional continuous kiln definitions. Description follows.
Appendix C – Text version

Appendix C contains 4 diagrams illustrating the definitions for bi-directional continuous kilns given in section 3.0 for options A, B, B-1-wom and D.

The first diagram illustrates the minimum requirements for option A, B, B-1-wom with 1 wet bulb. At the bottom, the kiln length is separated in 3 segments, the left segment is 60 feet long, the middle segment is 100 feet long, and the right segment is 60 feet long. At the top, track 1 is represented by an arrow that goes from right to left. The heat treatment zone is in the middle and the ramp-up zone is located on the far right. The heat treatment zone length is 34 feet, and the wet bulb is located within that zone. The ramp-up zone length is 73 feet. The middle part of the diagram contains the entering/exiting section at each end of the kiln, followed by the last third and first third of the kiln, and the main heating section located in the mid-third of the kiln. At the bottom, track 2 is represented by an arrow that goes from left to right. The ramp-up zone is on right. The heat treatment zone is the middle.

The second diagram illustrates the minimum requirements for option A, B, B-1-wom with 3 wet bulbs. At the bottom, the kiln length is separated in 3 segments, the left segment is 60 feet long, the middle segment is 100 feet long, and the right segment is 60 feet long. At the top, track 1 represented by an arrow that goes from right to left. The heat treatment zone is in the middle and the ramp-up zone is located on the far right. The heat treatment zone length is 56 feet, and 2 wet bulbs are located within the zone. The ramp-up zone length is 73 feet. The middle part of the diagram contains the entering/exiting section at each end of the kiln, followed by the last third and first third of the kiln, and the main heating section located in the mid-third of the kiln. At the bottom, track 2 is represented by an arrow that goes from left to right. The ramp-up zone is on right. The heat treatment zone and 1 wet bulb are the middle.

The third diagram illustrates the minimum requirements for option A, B, B-1-wom with 4 wet bulbs. At the bottom, the kiln length is separated in 3 segments, the left segment is 60 feet long, the middle segment is 100 feet long, and the right segment is 60 feet long. At the top, track 1 is represented by an arrow that goes from right to left. The heat treatment zone is in the middle and the ramp-up zone is located on the far right. The heat treatment zone length is 56 feet, and 2 wet bulbs are located within the zone. The ramp-up zone length is 73 feet. The middle part of the diagram contains the entering/exiting section at each end of the kiln, followed by the last third and first third of the kiln, and the main heating section located in the mid-third of the kiln. At the bottom, track 2 is represented by an arrow that goes from left to right. The ramp-up zone is on right. The heat treatment zone and 2 wet bulbs are the middle.

The fourth diagram illustrates the minimum requirements for option D with 2 dry bulbs per track. At the bottom, the kiln length is separated in 3 segments, the left segment is 60 feet long, the middle segment is 100 feet long, and the right segment is 60 feet long. At the top, track 1 is represented by an arrow that goes from right to left. The heat treatment zone is in the middle and the ramp-up zone is located on the far right. The heat treatment zone length is 67 feet, and 2 dry bulbs are located within the zone. The ramp-up zone length is 73 feet. The middle part of the diagram contains the entering/exiting section at each end of the kiln, followed by the last third and first third of the kiln, and the main heating section located in the mid-third of the kiln. At the bottom, track 2 is represented by an arrow that goes from left to right. The ramp-up zone is on right. The heat treatment zone and 2 dry bulbs are the middle.

Appendix D: bi-directional continuous kiln layout diagrams

Appendix D: bi-directional continuous kiln layout diagrams. Description follows.
Appendix D – Text version

Appendix D contains 4 diagrams illustrating the minimum requirements for bi-directional continuous kilns.

The first diagram illustrates the minimum requirements for option A, B and B-1-wom with 1 wet bulb and is entitled Minimum layout requirements for a bi-directional continuous kiln with 1 wet bulb. The kiln length is 220 feet (distance between the ends) and is the same as the side length (perpendicular to air flow) and is represented by an arrow at the bottom of the image. At the bottom, the kiln length is separated in 3 segments, the left segment is 60 feet long, the middle segment is 100 feet long, and the right segment is 60 feet long. The end of the kiln (parallel to air flow) is represented by an arrow at the right of the image. At the top, track 1 is represented by an orange arrow going from right to left in the kiln. The heat treatment zone is in the middle, and there is a ramp-up zone located on the far right. The heat treatment zone length is 34 feet, and the wet bulb is located in the mid-third of the main heating section. The ramp-up zone length is 73 feet (length of 2/3 of the entering/exiting section plus 1/3 of the main heating section). At the bottom, the ramp-up zone is on right, the heat treatment zone is the middle, and track 2 is represented by a green arrow that goes from left to right. The direction of the flow is represented by 2 vertical arrows indicating fan reversal. The maximum velocity is 0.5 m/second (100 feet/minute), the air velocity is measured on the exit side of the chamber of the load. Also see section 4.2.1.2 of this document.

The second diagram illustrates the minimum requirements for option A, B and B-1-wom with 3 wet bulbs and is entitled Minimum layout requirements for a bi-directional continuous kiln with 3 wet bulbs. The kiln length is 220 feet (distance between the ends) and is the same as the side length (perpendicular to air flow) and is represented by an arrow at the bottom of the image. At the bottom, the kiln length is separated in 3 segments, the left segment is 60 feet long, the middle segment is 100 feet long, and the right segment is 60 feet long. The end of the kiln (parallel to air flow) is represented by an arrow at the right of the image. At the top, track 1 is represented by an orange arrow going from right to left in the kiln. The heat treatment zone is in the middle, and the ramp-up zone is located on the far right. The heat treatment zone length is 56 feet (length of the mid-third of the heating section plus distance to the wet bulb), and 1 wet bulb is placed within the exiting of entering third of the main heating section on each track at 22 feet, and another wet bulb is located in the mid-third of the main heating section. The ramp-up zone length is 73 feet (length of 2/3 of the entering/exiting section plus 1/3 of the main heating section). At the bottom, the ramp-up zone is on right, the heat treatment zone is the middle, and track 2 is represented by a green arrow that goes from left to right. The third wet bulb is placed within the exiting or entering third of the main heating section on each track at 22 feet. The direction of the flow is represented by 2 vertical arrows indicating fan reversal. The maximum velocity is 0.5 m/second (100 feet/minute), the air velocity is measured on the exit side of the chamber of the load. Also see section 4.2.1.2 of this document.

The third diagram illustrates the minimum requirements for option A, B and B-1-wom with 4 wet bulbs and is entitled Minimum layout requirements for a bi-directional continuous kiln with 4 wet bulbs. The kiln length is 220 feet (distance between the ends) and is the same as the side length (perpendicular to air flow) and is represented by an arrow at the bottom of the image. At the bottom, the kiln length is separated in 3 segments, the left segment is 60 feet long, the middle segment is 100 feet long, and the right segment is 60 feet long. The end of the kiln (parallel to air flow) is represented by an arrow at the right of the image. At the top, track 1 is represented by an orange arrow going from right to left in the kiln, the heat treatment zone is in the middle, and the ramp-up zone is located on the far right. The heat treatment zone length is 78 feet (distance between wet bulbs), and 1 wet bulb is placed within the main heating section of each track. The ramp-up zone length is 51 feet (length of 2/3 of the entering/exiting section plus distance to wet bulb 1 from entering/exiting section). At the bottom, the ramp-up zone is on right, the heat treatment zone is the middle, and track 2 is represented by a green arrow that goes from left to right. The direction of the flow is represented by 2 vertical arrows indicating fan reversal. The maximum velocity is 0.5 m/second (100 feet/minute), the air velocity is measured on the exit side of the chamber of the load. Also see section 4.2.1.2 of this document.

The fourth diagram illustrates the minimum requirements for option A, B and B-1-wom with 4 dry bulbs and is entitled Minimum layout requirements for a bi-directional continuous kiln with 4 dry bulbs. The kiln length is 220 feet (distance between the ends) and is the same as the side length (perpendicular to air flow) and is represented by an arrow at the bottom of the image. At the bottom, the kiln length is separated in 3 segments, the left segment is 60 feet long, the middle segment is 100 feet long, and the right segment is 60 feet long. The end of the kiln (parallel to air flow) is represented by an arrow at the right of the image. At the top, track 1 is represented by an orange arrow going from right to left in the kiln, the heat treatment zone is in the middle, and the ramp-up zone is located on the far right. The heat treatment zone length is 67 feet (distance from the start of the mid-third of the main heating section). The dry bulb 1 track 1 is located in the first half of the mid-third of the main heating section and the dry bulb 2 track 1 Is located in the second half of the exiting third of the main heating section. The ramp-up zone length is 73 feet (length of 2/3 of the entering/exiting section plus 1/3 of the main heating section). At the bottom, the ramp-up zone is on the left, the heat treatment zone is the middle, and track 2 is represented by a green arrow that goes from left to right. The dry bulb 1 track 2 is located in the first half of the main heating section and the dry bulb 2 track 2 is located in the second half of the exiting third of the main heating section. The direction of the flow is represented by 2 vertical arrows indicating fan reversal. The maximum velocity is 0.5 m/second (100 feet/minute), the air velocity is measured on the exit side of the chamber of the load. Also see section 4.6.1.2 of this document.

Note: when the option prescribes the number and/or locations of bulbs and sensors based on the kiln length, the kiln length is always defined by airflow, regardless of the shape of the kiln.

Appendix E: wood packaging product thickness relative to treatment option selection

Appendix E figure 1. Description follows.
Description for figure 1

Figure 1 shows a wood pallet where the air flow is perpendicular to the wood boards on the top of the pallet, through the 2 sections between supporting boards between the top and the bottom of the pallet. In that case, the measure is the thickness of those wood pieces supporting the top and the bottom of the pallet.

Appendix E figure 2. Description follows.
Description for figure 2

Figure 2 shows a wood pallet where the air flow is parallel to the wood boards on the top of the pallet, through the 2 sections between the 3 boards at the bottom of the pallet. In that case, the measure is the width of the wood pieces supporting the top and the bottom of the pallet.

Appendix E figure 3. Description follows.
Description for figure 3

Figure 3 shows a wood pallet where the air flow is parallel to the wood boards on the top of the pallet, through the 2 sections between the wood blocks between the top and the bottom of the pallet. In that case, the measure is the thickness of the wood blocks supporting the top and the bottom of the pallet.

Appendix E figure 4. Description follows.
Description for figure 4

Figure 4 shows a wood pallet where the air flow is perpendicular to the wood boards on the top of the pallet, through the 2 sections between the wood blocks between the top and the bottom of the pallet. In that case, the measure is the width of the wood blocks supporting the top and the bottom of the pallet.

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