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Guidelines Part 7

Guidelines Part 7 Contents

DIVISION 4 - THERMAL EXPOSURE

Heat Exposure

  G7.27(1) Heat exposure - Application
  G7.27(2) Firefighting
  G7.28(1) Exposure limits - Using the ACGIH Standard
  G7.28(2) Clothing correction values
  G7.29-1 Heat stress assessment
  G7.29-2 Environmental parameters
  G7.29-3 Physiological measures
  G7.29-4 Heat stress assessment using a dry bulb thermometer or Humidex index
  G7.29-5 Exposure control plan
  G7.30-1 Engineering controls
  G7.30-2 Administrative controls
  G7.30-3 Personal protective equipment

Cold Exposure

  G7.33-1 Cold exposure - Application
  G7.33-2 Cooling power of wind (imperial units)
  G7.33-3 Cooling power of wind (metric units)
  G7.34-1 Cold stress assessment
  G7.34-2 Conversion
  G7.34-3 Exposure control plan
  G7.35-1 Engineering controls
  G7.35-2 Administrative controls
  G7.35-3 Work/warm-up schedule for a 4-hour shift
  G7.35-4 Personal protective equipment
  G7.36 Heated shelters
  G7.37-1 Clothing (whole body)
  G7.37-2 Clothing (extremities)

Guidelines Part 7 - Division 1 - Noise Exposure

G7.2 Exposure limits

Issued August 1999; Revised January 1, 2005

Section 7.2 of the OHS Regulation states:

An employer must ensure that a worker is not exposed to noise levels above either of the exposure limits:

(a) 85 dBA Lex daily noise exposure level, or

(b) 140 dBC peak sound level.

The daily noise exposure of a worker, Lex, is derived from the Leq measured with a noise dosimeter or integrating sound level meter (SLM) over a sample time. If a sample time, such as 30 minutes, is representative of the entire shift's noise then:

The measured sample Leq is equal to the Leq for the shift.
Lex can be regarded as a Leq corrected for those workers not working shifts of 8 hour duration.
Lex can be obtained from the measured Leq by applying a correction factor. To determine the correction, use the following nomogram:

Corrected Leq

For example, if the worker is exposed to a measured level of 88 dBA Leq for a period of 10 hours, the Lex equals 89 dBA (88 plus 1 =9).

In establishing noise exposure, dosimeter measurements cannot be used to determine peak sound levels. Peaks must be measured directly by the surveyor at the time of exposure using a noise meter set to "Peak" response and "C-weighting."

Occasionally, noise survey results may be questionable due to unrepresentative work conditions prevailing when the survey was done. In such cases, the Lex over a term longer than a normal workday shift may be more desirable. The Lex for other work periods may be obtained by direct measurement or by predicting Lex for the different conditions for the remaining days of a typical cyclical work period, such as a week. The final Lex value is obtained from the logarithmic mean of the Lex values for all days of the cycle.

G7.3-1 Noise measurement - When required and performance

Issued August 1999; Revised January 1, 2005; Revised April 4, 2007; Editorial Revision June 6, 2007

Regulatory excerpt
Section 7.3 of the OHS Regulation ("Regulation") states:

(1) If a worker is or may be exposed to potentially harmful levels of noise, or if information indicates that a worker may be exposed to a level exceeding 82 dBA Lex, the employer must measure the noise exposure.

(2) The noise exposure measurement must

(a) be performed in accordance with CSA Standard Z107.56-94, Procedures for the Measurement of Occupational Noise Exposure, as amended from time to time, except as otherwise determined by the Board, and

(b) be updated if a change in equipment or process affects the noise level or the duration of noise exposure.

(3) Except as otherwise determined by the Board, noise dosimeters and sound level meters used for measuring noise exposure must meet the requirements of ANSI Standard S1.25-1991, Specification for Personal Noise Dosimeters, as amended from time to time.

(4) The employer must inform affected workers of the results of any noise exposure measurement and the significance of the measurement to risk of hearing loss.

Purpose of guideline
The purpose of this guideline is to

Discuss the use of sound level meters (SLMs) under section 7.3(1)
Highlight the current applicable standard by which noise exposure measurement must be performed under section 7.3(2)(a)
Present some specifications for personal noise dosimeters under section 7.3(3)
Discuss considerations when using older dosimeters that have a criterion level other than 85 dBA.

Use of SLMs under section 7.3(1)
Noise exposure measurements conducted in accordance with section 7.3(1) of the Regulation serve as an initial screening survey to determine if further, more detailed surveys are required. Noise surveys may be carried out with non-integrating SLMs. However, the data obtained must represent an 8-hour exposure level (Lex) for comparison with the screening standard of Lex of 82 dBA. The types of noise, patterns of work, times of breaks, production variables, and worker exposure hours combined with carefully selected grab samples from the SLM should be considered when determining the occupational noise exposure.

Current applicable CSA Standard for procedures for the measurement of occupational noise exposure
For the purposes of section 7.3(2)(a), CSA Standard Z107.56-06, Procedures for the Measurement of Occupational Noise Exposure is the current applicable CSA standard. CSA Standard Z107.56-06 contains the minimum acceptable procedures for the measurement of occupational noise exposure. Note that some of the amendments to CSA Standard Z107.56 between the 1994 and 2006 version include the addition of

References to newer and additional standards, some of which must be followed where applicable
A statement regarding how Lex can be determined from Leq (Annex C Division C.4)
A requirement for the microphone to be located above the outside edge of the wearer's shoulder or as near as is feasible (section 6.4.4.3). The 1994 version of the standard had stated that the microphone shall be located on the top of the wearer's shoulder or as near as is feasible
A warning about false peaks, especially when fitting or removing microphones and while at breaks (section 6.4.4.3)
A recommendation that unwitnessed high peaks should be investigated (section 6.4.4.4)

Also, CSA Z107.56-06 no longer includes references to Pascal squared hour (Pa²h). Instead it refers to Lex, as does the Regulation.

WorkSafeBC has prepared two booklets entitled Occupational Noise Surveys and Basic Noise Calculations to assist employers in conducting a noise survey.

The booklets offer guidelines to acoustical consultants and others who need to comply with WorkSafeBC'S minimum acceptable requirements for surveys. Inquiries concerning the acceptability of other standards for measuring occupational noise exposure should be directed to the Industry and Labour Services department for evaluation.

Specifications for personal noise dosimeters
For the purposes of section 7.3(3), ANSI Standard S1.25-1991, Specification for Personal Noise Dosimeters is the current applicable standard. CSA Standard Z107.56-06, Procedures for Measurement of Occupational Noise Exposure specifies Type 2 tolerance for both integrating sound level meters and noise dosimeters. Type 2 relates to the accuracy required to measure occupational noise exposure.

A noise dosimeter is to be set as follows:

Criterion level = 85 dBA
Threshold level below or = 80 dBA or at "Off"
Exchange rate q = 3

Considerations when using dosimeters that are not or cannot be set to a criterion level of 85 dBA
It is important to know the criterion level of a dosimeter and to make appropriate adjustments to the readings if necessary. Older noise dosimeters in use may still be calibrated to read 100% noise dose when exposed to a sound level of 90 dBA averaged over an 8-hour period. To check a dosimeter's criterion level, inject a known noise dose using a calibrator generating a known level for a fixed period of time, and read the percentage noise dose acquired. For example, a Quest brand calibrator generates a noise dose of 110 dBA for 32 seconds. A dosimeter calibrated to a criterion level of 90 dBA would result in a reading of 11.1%; a dosimeter calibrated to a criterion dose of 85 dBA would read 35%. Older dosimeters, regardless of the criterion level they are set to, can still provide an accurate Leq as long as they are used with a threshold level equal to or less than 80 dBA and the appropriate technique for converting Leq from their noise dose reading and the sampling duration is used.

Availability of standards
CSA standards are available by contacting CSA International in their office in Richmond, B.C. or through their website at:
http://www.csa.ca/

ANSI standards are available through their website at:
http://www.ansi.org

G7.3-2 Noise exposure data collected by prevention officers

Issued August 1999; Revised January 1, 2005; Editorial Revision February 6, 2006

Noise exposure measurements made by prevention officers through fieldwork should be copied to the Hearing Loss Prevention Section for inclusion in the noise level database. The following fields should be completed to facilitate record keeping:

Firm and location number
Industry Classification Unit (CU)
Occupation name for workers sampled
Noise exposure level in dBA Lex
Date of sampling
Inspection report (IR) number
Descriptive comments about the work activity and the equipment used

Officers should use the Noise Survey Template standard form supplied by the Hearing Loss Prevention Section to complete this information.

G7.4 Exemption

Issued August 1999; Revised January 1, 2005; Editorial Revision October 2005; Editorial Revision February 6, 2006

Section 7.4 of the OHS Regulation states:

7.4 An employer is not required to measure the noise exposure of a worker if

(a) based on other information, the employer identifies the worker as being exposed to noise in excess of an exposure limit, and

(b) the employer establishes an effective noise control and hearing conservation program for that worker.

Under section 7.4, an employer does not need to undertake a noise exposure measurement program if it can be determined a worker is exposed to noise in excess of the limits established by section 7.2 by some other means, such as the following:

The peak noise level limit of 140 dBC is routinely exceeded.
Short-term Leq measurements indicate that 85 dBA Lex is exceeded on a daily basis (for example, Leq measures at 100 dBA over a 15-minute period).
A database of worker noise exposures indicates members of a trade/occupation class to be overexposed on a daily basis. The Hearing Loss Prevention Section maintains an extensive database of this type. Contact them at HRNGCONS@worksafebc.com for noise exposure information. Refer also to OHS Guideline G7.8-4 for information on construction trades.
Noise emission labels on tools or equipment indicate there is a strong possibility of overexposure to noise when used or operated.
Exposure for groups of workers can be extrapolated from a database of job activities and corresponding partial noise exposures (for example, the Lex of firefighters based upon emergencies attended, equipment involved, typical Leq readings for the vehicles and average duration of each exposure).

If the employer uses one of the above means to determine that exposure is above the limits in section 7.2, then section 7.4(b) requires the employer to implement a noise control and hearing conservation program in accordance with section 7.5, except for noise measurement in 7.5(a).

G7.5-1 Program - Education and training

Issued January 1, 2005

Section 7.5(b) of the OHS Regulation states:

If noise in the workplace exceeds either of the noise exposure limits, the employer must develop and implement an effective noise control and hearing conservation program with the following elements: . . .

(b) education and training; . . .

The education and training of workers exposed to noise above the stated exposure limits as defined in section 7.2 should include:

The results of any noise exposure measurements
The effects of noise on hearing
The proper use and maintenance of hearing protection
The purpose of hearing testing

Two brochures, Hear for Good and Testing Your Hearing, How and Why, and a video, The Hearing Video, are available to assist employers in implementing the education and training components of the program. The brochures are available on the WCB web site at:
http://www2.worksafebc.com/Topics/HearingLossPrevention/Resources.asp

Information on how to order printed brochures and the video is provided at:
http://www.worksafebc.com/publications/ how_to_order_publications_and_videos/.

G7.5-2 Annual program review

Issued August 1999; Revised January 1, 2005; Editorial Revision October 2005; Editorial Revision February 6, 2006

Section 7.5(g) of the OHS Regulation states:

If noise in the workplace exceeds either of the noise exposure limits, the employer must develop and implement an effective noise control and hearing conservation program with the following elements: . . .

(g) annual program review.

The employer needs to review the noise control and hearing conservation program at least annually to ensure its effectiveness. The review should address:

The need for further noise measurement
The education and training of workers regarding noise exposure
The adequacy of noise control measures
Selection and use of hearing protection
Hearing testing and information on the rate and extent of occupational hearing loss

The Hearing Loss Prevention Section has produced a Hearing Conservation Program Evaluation Checklist (pdf 11KB) and sample written hearing conservation programs (Sample Written Hearing Conservation Programs -- small employer (pdf 30KB) and Sample Written Hearing Conservation Programs -- large employer (pdf 38KB)) to assist employers in achieving compliance with program requirements. These are available on the WorkSafeBC web site at:
www2.worksafebc.com/Topics/HearingLossPrevention/Resources.asp

G7.6-1 Investigating controls

Issued August 1999; Revised January 1, 2005

Section 7.6 of the OHS Regulation states:

If a worker is exposed to noise above a noise exposure limit, the employer must

(a) investigate options for engineered noise control, and

(b) when practicable, implement one or more of those options to reduce noise exposure of workers to or below the exposure limits.

When noise exposure exceeds either exposure limit set out in section 7.2 of the OHS Regulation, the employer is required to investigate ways of reducing noise exposure. An employer may achieve this through review of information provided in trade journals specific to their industries, through contacts in the business or trade associations, or by consulting an acoustical engineer or occupational hygienist.

The use of hearing protection devices should be considered a temporary measure only. Implementation of successful noise control will reduce the ongoing costs of a hearing conservation program in the long run.

G7.6-2 Implementing controls

Issued August 1999; Revised January 1, 2005

Section 7.6 of the OHS Regulation states:

If a worker is exposed to noise above a noise exposure limit, the employer must

(a) investigate options for engineered noise control, and

(b) when practicable, implement one or more of those options to reduce noise exposure of workers to or below the exposure limits.

Section 7.6(b) requires the employer, when practicable, to implement one or more options for engineered noise control to reduce worker exposure to or below the exposure limits. "Practicable" as defined in section 1.1 of the OHS Regulation, means "that which is reasonably capable of being done." The incentive for controlling noise increases with the degree of overexposure and associated increasing risk of noise-induced hearing loss.

Noise control solutions lie on a continuum, starting with quick fixes, through regular maintenance, extending through low-cost solutions to large capital expense programs (see examples of controls below). One guide in deciding whether noise control is practicable is to determine if the control measure has been adopted by the industry and found acceptable. Although noise control frequently may be technically capable of being done, it may prove to be impracticable. In some instances, noise control solutions are only achieved through long-term research and development programs or complete rebuilds. However, research and development programs may place an unreasonable economic burden on an individual employer and are therefore considered impracticable. Complete rebuilds would likely also be impracticable unless the employer is, for other business reasons, planning to rebuild a facility.

Some examples of typical means for engineered noise control are set out below.

Repairing: Cover holes in walls/windows/doors of noise enclosures/operator booths, engine mufflers, doors seals, and sills.
Fitting: Install compressed air exhaust mufflers, air jet noise silencer nozzles, etc.
Changing: Change "screaming" saw blades for quieter blades.
Applying: Apply mechanical damping treatment to steel panels in impact situations, shock absorber configurations in material handling, duct silencers for fan noise, etc.
Enclosing: Enclose planers, molders, punch presses, air compressors, and circular saws.
Isolating: Provide noise enclosure booths (complete or partial) for graders, planermen, and the operators of mobile equipment, veneer lathes, headrigs, edgers, and cutoff saws.
Installing: Install absorbent panels on walls/ceiling near noisy tools, absorbent ceiling baffles, etc.
Substituting: Provide quieter machines/tools/processes such as hydraulic rather than pneumatic power or impact force.
Developing: Develop treatment for band mills, hard rock drills, electric arc furnaces, etc.
Modifying: Change the work process or equipment.
Designing and acoustically treating: Modify the work area.

G7.7-1 Selection of hearing protection

Issued August 1999; Revised January 1, 2005

Section 7.7(1)(c) of the OHS Regulation states:

(1) If it is not practicable to reduce noise levels to or below noise exposure limits, the employer must . . .

(c) give to affected workers hearing protection that meets the requirements of CSA Standard Z94.2-02, Hearing Protection Devices - Performance, Selection, Care, and Use, as amended from time to time, except as otherwise determined by the Board, and maintain the hearing protection so that it continues to meet those standards, and

Selection criteria

The current applicable standard is the CSA Standard Z94.2-02 Hearing Protection Devices - Performance, Selection, Care, and Use. This standard provides a process for selecting adequate hearing protection for noise-exposed individuals, taking into account factors such as:

Worker noise exposure
Worker hearing ability
Use of other personal protective equipment
Temperature and climate
Physical constraints of the worker or work activity
Comfort

Comfort is a selection criterion specified in the standard and is considered as important as attenuation (sound reduction). It is important since workers will be more likely to properly wear their hearing protectors if there is a comfortable fit, thereby increasing self-compliance.

Hearing protection classification/grade

The CSA Standard Z94.2-02 Hearing Protection Devices - Performance, Selection, Care, and Use has two tables that are to be used together in selecting hearing protection. The first table provides information on the recommended class or grade of protector for the worker's noise exposure. There are two different rating systems, based on two different ways of measuring hearing protector attenuation. The grade rating method is more reflective of the attenuation the protection will likely deliver in the workplace. Just as Class A protection has more attenuation than Class B, Grade 4 protection has more than Grade 3, and so on.

The second table provides guidance on protection outcomes to prevent overprotection -- the wearing of hearing protection with too much attenuation. Overprotection is undesirable as it:

May prevent workers from hearing audible warning signals
Reduces the ability of workers to verbally communicate in the noisy environment, resulting in temporary removal of hearing protection
Results in the need for workers to "yell" at one another, causing voice strain
Limits a worker's ability to hear changes in machinery or process performance that may indicate developing production problems
Does not provide any additional protection against noise-induced hearing loss

Application of the selection criteria in the standard typically means more than one style and class or grade of hearing protector should be made available to workers. For example, if a worksite has noise exposures ranging from 85-98 dBA Lex, then Class A and Class B (Grade 3, 2, and 1) protection should be supplied, to accommodate the criterion "daily noise exposure of the worker." Similarly, if there are workers with hearing impairment at the worksite, Class A and B (Grade 3, 2, and 1) protection should be supplied to accommodate the criterion "worker hearing ability." In addition, earplugs and earmuffs will likely have to be supplied to accommodate the criteria "use of other personal protective equipment," "temperature and climate," and "physical constraints of the worker." This last criterion includes such aspects as very small or very large ear canals, sensitive skin in the ear canal, and unusual head size or shape.

Specialized hearing protection

Beyond these conventional protectors, the following types of workers may need more specialized hearing protection, due to listening demands:

Workers with significant hearing losses
Supervisors
Trades workers
Vehicle operators
Instructors
Musicians (performers as well as technical support personnel)
Hospitality workers

Where one- or two-way radio communication is required, a commercially manufactured hearing protection device with built-in speakers and/or microphone should be supplied. There is an entire section in the 2002 CSA standard devoted to specialized hearing protection.

The standard also states that hearing protection must be visually inspected during the annual hearing test for condition and fit.

Further information regarding hearing protection is available in the brochure Hear for Good and in the standard practice manual Sound Advice. Both are available on the WCB web site at:
www2.worksafebc.com/Topics/HearingLossPrevention/Resources.asp

CSA standards are available by contacting CSA International in their office in Richmond, B.C., or through their website at:
http://www.csa.ca/

G7.7-2 Warning signs and hearing protection

Issued August 1999; Revised January 1, 2005

Section 7.7(1)(b) of the OHS Regulation states:

(1) If it is not practicable to reduce noise levels to or below noise exposure limits, the employer must . . .

(b) post warning signs in the noise hazard areas . . .

Section 7.7(2) of the OHS Regulation states:

(2) Workers in a posted noise hazard area must wear hearing protection.

Sometimes workers move in and out of noise hazard areas during their workday. Supervisors or other workers whose duties require them to routinely work in posted noise hazard areas must be provided with, and wear, hearing protection in the posted areas. Workers who briefly and infrequently pass through posted noise hazard areas do not need to wear hearing protection, except in areas where the exposure limit for peak sound level is exceeded.

The employer may establish workplace policies which exceed the requirements of the OHS Regulation regarding the use of hearing protection in noise hazard areas. For example, the employer may instruct workers that use of hearing protection is mandatory for all workers in any designated noise hazard area in their facility.

Hearing protection does not need to be worn when the source of noise that makes the area hazardous is shut down.

G7.8-1 Annual hearing tests

Issued August 1999; Revised January 1, 2005; Editorial Revision April 4, 2007

Regulatory excerpt

Section 7.8(1) of the OHS Regulation ("Regulation") states:

The employer must give workers who are exposed to noise that exceeds noise exposure limits

(a) an initial hearing test as soon as practicable after employment starts, but not later than 6 months after the start of employment, and

(b) a test at least once every 12 months after the initial test.

Purpose of guideline
The purpose of this guideline is to discuss the application of section 7.8(1) to industries in which workers may not be employed continuously for more than six months.

Background
There are a number of industries where noise levels are known to exceed the exposure limits in section 7.2 and in which workers may not be employed continuously for more than six months; however, workers are usually employed in these industries for many months each year. Examples of such industries are fish processing, shipbuilding, logging, and construction.

Level of risk

Some industries, such as agriculture, involve workforces that are a mix of stable and seasonal workers, who may be exposed to a range of noise levels. Typically, fieldworkers will be exposed to low noise levels and would not need to be tested. Persons most at risk would likely include those farmers, ranchers, and workers who operate equipment with high noise levels, and those who work in some indoor operations involving raising of animals or fowl.

Program options for testing workers

Section 7.8(1) establishes an obligation to test any new worker who is exposed above the noise exposure limits, not just those workers who stay for 6 months with the employer. If the employment lasts less than 6 months, the test should be done within that timeframe or period. In this context, the employer should have a reasonably effective program for testing workers. Two common ways of doing this are as follows:

Arrange for a hearing testing contractor to visit the place of workplace
Set up an in-house testing program

With regard to the first option, the visits may be at regular intervals selected by the employer, such as every three months. Alternatively, the employer might arrange the visits for a convenient time in a project, such as before workers leave town to go to a remote area. In either case, if the employer sets up a reasonable program, WorkSafeBC will not be concerned if some workers missed the testing because they started work just after, or finished employment just before, a testing contractor arrived.

In some situations, for example in rural agricultural operations, options other than the two listed above may be appropriate. For example, workers may be sent to a testing facility where available in a nearby town, or workers from a number of farms or ranches may be tested at a location common to them, or at another workplace in the area with an in-house testing program.

Out of province employers
A similar issue arises for out-of-province employers who operate in B.C. for short periods of time. If the workers are working in B.C. for a total of 6 months or more in a year, then hearing tests meeting the requirements of section 7.8 are required for those workers.

G7.8-2 Authorized hearing testers

Issued August 1999; Revised January 1, 2005

Section 7.8(2) of the OHS Regulation states:

Hearing tests must be administered by a hearing tester authorized by the Board.

A list of authorized hearing test contractors is available on the WCB web site at:
www2.worksafebc.com/Topics/HearingLoss/Prevention/FAQ.asp

Details regarding the standards, criteria, and processes for authorizing testers and for removing authorization are contained in the Administration Procedures - Industrial Audiometry. This document is available on the WCB web site at: www2.worksafebc.com/Topics/HearingLossPrevention/IATCertification.asp

Authorized testers have been trained to:

Obtain relevant medical history information
Record the hearing tests in a manner required by the Board
Advise the worker of the test results
Counsel the worker on the use and maintenance of hearing protection
On request, provide a copy of the test results to the worker

The employer must not disclose or publish a worker's medical history information except as permitted by the Board, in accordance with section 156(1)(a) of the Workers Compensation Act. Section 156 states that:

(1) A person must not disclose or publish the following information, except for the purpose of administering this Act and the regulations or as otherwise required by law:

(a) information obtained in a medical examination, test or X-ray of a worker made or taken under this Part, Part 4 or the regulations, unless the worker consents or the information is disclosed in a form calculated to prevent the information from being identified with a particular person or case; . . .

An employer should also not retain a copy of a worker's medical history.

G7.8-3 Hearing test results

Issued August 1999; Revised January 1, 2005; Editorial Revision 2005; Editorial Revision February 6, 2006

Section 7.8(3) of the OHS Regulation states:

The employer must ensure that the authorized hearing tester sends the test results to the Board.

The Hearing Loss Prevention Section maintains a database of hearing tests. Annual statistical reports are provided to all employers that submit hearing test data, confirming numbers and categories of tests processed. The report includes a breakdown by type and category of each hearing test. It is expected that the employer will use this report to determine the rate and extent of occupational hearing loss in their workers when reviewing the hearing conservation program on an annual basis. Prevention officers may obtain this type of statistical report for a particular firm and location, at any time, to assist in evaluating compliance.

G7.8-4 Construction industry

Issued August 1999; Revised January 1, 2005

Section 7.8 of the OHS Regulation states:

(1) The employer must give workers who are exposed to noise that exceeds noise exposure limits

(a) an initial hearing test as soon as practicable after employment starts, but not later than 6 months after the start of employment, and

(b) a test at least once every 12 months after the initial test.

(2) Hearing tests must be administered by a hearing tester authorized by the Board.

(3) The employer must ensure that the authorized hearing tester sends the test results to the Board.

In October 1987, an agreement was established between the Board and the construction industry (joint worker/employer representation through the B.C. Construction Association) that workers employed in certain occupations in some construction industry classifications are routinely exposed to noise in excess of the exposure limits. The agreement applies to the classification units (CUs) in the following subsectors:

7210 General Construction (with the exception of subunits 721016, 721023, 721029, 721030, 721044 which are not considered hazardously noisy)
7220 Heavy Construction
7230 Road Building

Noise-exposed occupations in the construction industry

In these CUs, a worker employed in one of the following occupations is to be considered as routinely exposed to noise in excess of the exposure limits:

Bricklayer
Carpenter
Concrete worker (around a pump, vibrator, jack hammer, or powered finishing equipment)
Driller
Drywaller (shooting track or boarding)
Electrician
Form worker
Foreman
Framer
Labourer
Mobile equipment operator
Pipefitter
Plumber
Roofer (shake, tar/gravel, membrane, shingle)
Sandblaster
Steel erector
Supervisor
Truck driver
Welder/fabricator

A worker in one of the above occupations should normally be part of a hearing test program meeting the requirements of section 7.8. If any worker in one of the listed occupations is not part of a hearing test program, orders may be written on the employer without measuring noise exposure of the worker. There is an extensive noise database documenting exposures for these occupations; the database was established in the mid-1980s and updated in the late 1990s. However, the officer will consider any evidence presented by the employer showing that a particular worker need not be on a hearing test program. For example, noise dosimetry carried out in June 1995 indicates that some mobile equipment operators (operators of modern tracked excavators and front-end loaders) have noise exposure levels below 85 dBA Lex. Advancements in the engineering of engine exhaust, hydraulic, and fan components on this equipment have resulted in lower noise exposures for the operators.

Note that the requirement for a hearing test program is not restricted to the listed occupations. There may be other occupations in these CUs in which workers are exposed to noise in excess of the exposure limits.

Payment for a construction worker's hearing tests

To assist construction industry employers in the above CUs to comply with the hearing test program requirements, the Board has established:

A central registry of hearing test results
A card validation system so each construction worker can show when his/her hearing was tested
A program to pay an authorized hearing test agency a fee per hearing test performed

The Board sets the fee paid to the hearing test agency for each test. The funding for this program is collected from the construction industry as a whole by charging an additional assessment to the CUs referred to above. This is pursuant to section 113(5) of the Workers Compensation Act, which provides that the Board may charge a class or subclass with the cost of investigations, inspections, and other services provided to the class or subclass for the prevention of injuries and illness.

An employer in one of the above CUs may comply with the requirements of section 7.8 without using the Board-administered program if the employer wishes. However, employers who participate in and comply with the Board's program are exempt from the obligation to conduct noise exposure measurement under section 7.4 of the OHS Regulation.

G7.9 Test records

Issued August 1999; Revised January 1, 2005; Editorial Revision October 2005; Editorial Revision February 6, 2006

Section 7.9 of the OHS Regulation states:

The employer must keep records of

(a) the annual hearing test results for each worker, which must

(i) be kept as long as the worker is employed by the employer, and

(ii) be kept confidential and not released to anyone without the written permission of the worker, or as otherwise required by law,

(b) the education and training provided to workers, and

(c) the results of noise exposure measurements taken under section 7.3.

Original copies of WCB Form H45E32 (the blue and white audiogram form) need not be present onsite at the worksite to fulfill the requirements of section 7.9. The employer may choose to have the hearing test contractor who conducted the tests maintain the hearing test records on behalf of the employer, or to have an occupational health services provider employed by the firm retain the records. Such arrangements should be set out in a written agreement.

A prevention officer may ask for other evidence of compliance with section 7.8 (provision of annual hearing tests to noise exposed workers) such as a copy of the Hearing Conservation Annual Report. This report is provided every February to all employers who submitted hearing test results to the Board in the previous year. The report includes a list of all workers tested (Forms Processed List) and a statistical breakdown of tests into various categories. The Hearing Loss Prevention Section can also provide an officer or employer with year-to-date summaries of the number of tests carried out and a list of workers tested for a given firm and year.

On construction sites, noise exposed workers should normally carry a current Record of Hearing Test card validating that they have been tested. The worker may be asked by a prevention officer to show the test record card.

An officer may ask the employer to obtain actual copies of hearing tests from the hearing test contractor if the officer feels this is necessary to verify compliance. The contractor should provide these to the employer on request.

Guidelines Part 7 - Division 2 - Vibration Exposure

G7.11-1 Exposure limits - hand-arm vibration

Issued August 1999; Revised January 1, 2005

Section 7.11(a) of the OHS Regulation states:

The employer must ensure, to the extent practicable, that workers are not exposed to vibration in excess of the limits specified in

(a) for hand-arm vibration, the American Conference of Governmental Industrial Hygienists publication entitled Threshold Limit Values and Biological Exposure Indices, dated 2003, as amended from time to time;
...

except as otherwise determined by the Board

The American Conference of Governmental Industrial Hygienists' publication includes the following table of recommended daily limits of exposure (TLVs) to frequency-weighted acceleration.

TLVs for exposure of the hand to vibration in x_h, y_h, or z_h directions

Total daily exposure duration	TLV of the dominant, frequency-weighted (rms), component acceleration which shall not be exceeded ms^-2
4 hours and less than 8	4
2 hours and less than 4	6
1 hour and less than 2	8
Less than 1 hour	12

(rms = root mean square, ms^-2 = metres per second squared)
Note: In this case, the value of the frequency-weighted acceleration (x_h, y_h, or z_h) refers to the three perpendicular x-, y-, and z-axes as it applies to the hand. The term "dominant" means that usually only one axis is dominant. If one or more axes exceeds the total daily exposure, then the TLV has been exceeded.

The OHS Regulation recognizes, in the phrase "to the extent practicable" in section 7.11, that there are circumstances in which the exposure limit cannot be fully complied with. In such circumstances, section 7.11 requires the employer to reduce the exposure using all practicable means currently available (see OHS Guideline G7.13 for further information), even if the exposure limit cannot be achieved.

Employers will be considered to have complied with section 7.11(a) if they can demonstrate that they have carried out an assessment of the risk of hand-arm vibration (HAV) by:

1. making a competent estimate of worker exposure in comparison with the TLV by using:

vibration data published as web databases or in the technical/scientific literature,
vibration data for the relevant tools supplied by tool manufacturer,
on-site vibration measurements made by a consultant, or, knowledgeable person
vibration data obtained by industry association, and
duration of typical, daily contact with the source of vibration

2. identifying the main contributors to the worker's HAV risks by using the vibration data collected to rank-order the sources of HAV to which the worker is exposed.

3. identifying and considering all available HAV risk controls. For example (see also G7.13):

selection of new vibration-reduced tools
investigating alternative ways of working which reduce HAV exposure
ensuring workers always use appropriate tools for the job
ensuring the proper bits (e.g. chisels and abrasive discs) are inserted into the tools
ensuring the tools are maintained in good condition (including dynamically balanced)
minimizing the worker's daily exposure time by spreading the job over more days and by job rotation with other workers

4. monitoring the effects of the implemented risk control measures, and adjusting control measures as necessary.

5. completing a written record of the above steps.

G7.11-2 Exposure limits - whole-body vibration

Issued August 1999; Revised January 1, 2005

Section 7.11(b) of the OHS Regulation states:

The employer must ensure, to the extent practicable, that workers are not exposed to vibration in excess of the limits specified in . . .

(b) whole-body vibration, ANSI Standard S3.18-2002/ISO 2631-1-1997, Mechanical Vibration and Shock - Evaluation of Human Exposure to Whole Body Vibration - Part 1: General Requirements, as amended from time to time;

except as otherwise determined by the Board.

With respect to section 7.11(b), Appendix B of ANSI S3.18-2002/ISO 2631-1:1997, Mechanical Vibration and Shock - Evaluation of Human Exposure to Whole-Body Vibration - Part 1: General Requirements, addresses the health effects of vibration on the human body and defines a "health caution guidance zone" for daily exposures of 4 to 8 hours, as follows:

Within the zone - caution is indicated with respect to potential risks for adverse health effects
Above the zone - adverse health risks are likely
Below the zone - adverse health effects have not been clearly documented and/or objectively observed

Whole-body vibration exposure limits in x, y, or z directions

Daily Exposure Duration	Values of the dominant, frequency-weighted (rms), component acceleration, ms^-2
	No clear effects	Caution	Health risks likely
4 hours	Less than 0.6	0.6 to 1.1	Greater than 1.1
8 hours	Less than 0.5	0.5 to 0.9	Greater than 0.9

(rms = root mean square, ms^-2 = metres per second squared)

Employers will be considered to have complied with section 7.11(1)(b) if they can demonstrate that they have carried out an assessment of the risk of whole-body vibration (WBV) by:

1. making a competent estimate of worker exposure in comparison with the exposure limits by using:

vibration databases on the internet or in the technical/scientific literature, or
vibration data supplied by the equipment manufacturer, or
on-site vibration measurements made by a consultant, or knowledgeable person
relevant data obtained through an industry association, and
duration of typical, daily contact with the source of vibration.

2. identifying the main contributors to the worker's risk. This involves using the data collected in the estimate to rank-order the sources of WBV to which the worker is exposed.

3. identifying and considering all available WBV risk controls. For example (see also G7.13):

in selection of new vibration-reduced equipment (eg suspended cabs and suspended seats)
investigating alternative ways of working which reduce WBV exposure
ensuring workers always use equipment appropriately
ensuring surfaces on which vehicles operate are regularly graded and free of irregularities (potholes and bumps etc.)
ensuring the equipment is maintained in good condition
minimising the worker's daily exposure time by spreading the job over more days and by job rotation with other workers.

4. monitoring the effects of the implemented risk control measures, and adjusting control measures as necessary.

5. completing a written record of the above steps.

G7.12 Evaluation

Issued August 1999; Revised January 1, 2005

Section 7.12 of the OHS Regulation states:

The evaluation of hand-arm vibration and whole-body vibration must be conducted by the employer in accordance with

(a) for hand-arm vibration, ISO Standard 5349-1:2001, Mechanical Vibration - Measurement and Evaluation of Human Exposure to Hand-transmitted Vibration - Part 1: General Requirements and ISO Standard 5349-2:2001, Mechanical Vibration - Measurement and Evaluation of Human Exposure to Hand-transmitted Vibration - Part 2: Practical Guidance for Measurement at the Workplace, as amended from time to time;

(b) for whole-body vibration, ANSI Standard S3.18-2002/ISO 2631-1-1997, Mechanical Vibration and Shock - Evaluation of Human Exposure to the Whole Body Vibration - Part 1: General Requirements, as amended from time to time;

except as otherwise determined by the Board.

In the exposure limit tables presented in OHS Guidelines G7.11-1 and G7.11-2 for hand-arm vibration (HAV) and whole-body vibration (WBV), acceleration limits are listed according to an "axis." The reason for this is that the body's response to vibration depends on the direction along which vibration enters the body. For both HAV and WBV, three perpendicular "biodynamic" axes (the x-, y-, and z-axes) are defined. The directions of these axes are described here.

Axes of vibration

Axis	Hand-arm vibration (HAV)	Whole-body vibration (WBV)
x-axis	Through the hand, from top towards the palm	Through the body, from the back towards the chest
y-axis	From the right side to the left side, parallel to the knuckles	From the right side to the left side
z-axis	From the wrist through to fingers, parallel to top of the hand	From the feet (or buttocks) to the head

Usually acceleration is dominant along one axis; for whole-body vibration this is often the z-axis.

For the measurement of vibration (HAV and WBV), measured accelerations are frequency-weighted according to the frequency weightings defined in the latest ISO and ANSI standards. The frequency-weighted accelerations can then be compared with criterion values/exposure limits, which are also expressed in terms of frequency-weighted acceleration. See OHS Guidelines G7.11-1 and G7.11-2 for exposure limits for HAV and WBV, respectively.)

The techniques for measurement and assessment of vibration now resemble those for noise, where frequency-weighted sound levels are measured and compared to criterion frequency-weighted sound levels in dBA.

G7.13 Exposure control plan

Issued August 1999; Revised January 1, 2005

Section 7.13 of the OHS Regulation states:

The employer must, if a worker is or may be exposed to vibration in excess of the vibration exposure limits, develop and implement an exposure control plan that meets the requirements of section 5.54(2).

A basic element of an exposure control plan is to determine the severity of the exposure to the agent. Not all equipment presents a hazard from vibration. Examples of equipment that may present a hazard to workers from either hand-arm vibration or whole-body vibration are listed below.

Some equipment that may present a vibration hazard

Hand-arm vibration	Whole-body vibration
Chainsaws, brush cutters, mowers Power saws for cutting metal, wood and stone Percussive tools (such as air-driven drills, wrenches, chisels, hammers, pavement breakers, and riveters or in swaging and flanging) Concrete vibrators Concrete surface preparation equipment Grinders, sanders, polishers, screwdrivers and other rotary tools Sand and aggregate compactors	Log decks Operator cabs for heavy equipment (commonly used in construction and forestry e.g. construction and mine haul & logging trucks, skidders) Forklift trucks, dump trucks Tracked vehicles, excavators, bulldozers, backhoes, scrapers, graders, front end and log loaders Snow removal vehicles Farm tractors Helicopters

When there is a reasonable expectation that vibration presents a significant hazard, the exposure limits in section 7.11 should be considered in the purchase and design of new equipment. In determining whether an exposure control plan is required, the duration of daily exposure and the operating conditions should be taken into consideration, as well as any reports of injury and disease from workers using existing equipment. Equipment that is used less than 0.5 hour per day is not likely to present a significant long-term hazard from vibration, except for the most highly vibrating equipment. It is prudent to regard regular prolonged use of any high-vibration tool or machine as hazardous, especially if it causes tingling or numbness in the user's fingers after about 5 to 10 minutes of continuous operation.

Some useful references in assessing equipment for vibration are the following publications by the Health Safety Executive in the United Kingdom: Hand-Arm Vibration (HSG88, 1994) and Vibration Solutions - Practical Ways to Reduce the Risk of Hand-Arm Vibration Injury (HSG170, 1997).

Evaluating equipment for potential for vibration

To evaluate the potential for vibration with respect to the exposure limits referred to in section 7.11, information on the vibration characteristics of the equipment or machinery is to be obtained. For example:

Obtaining information from the supplier of the equipment: The employer should ask the following questions to obtain information from a supplier or designer:
- Does the equipment meet the exposure limits in the referenced standards?
- What is the frequency-weighted acceleration of the equipment?
- Under what operating conditions were the measurements made?
- Which published standard was used when conducting the evaluation?
Researching the relevant literature and available databases: The Swedish National Institute for Working Life maintains a vibration database, which contains vibration levels for 60 vehicles. It can be viewed on the Internet at:
http://umetech.niwl.se/eng/wbvhome.lasso.
Measuring frequency-weighted acceleration values of designed equipment or of equipment before purchase: These determinations are to be conducted in accordance with a standard acceptable under section 7.12 of the OHS Regulation.

Options for control measures

Control measures to protect against hand-arm vibration (HAV) include the following:

Ensure the tool is properly maintained, serviced and adjusted and anti-vibration mounts and suspended handles are replaced before they deteriorate.
Keep tools e.g. chisels sharpened.
Fit grinders with effective, balanced, grinding discs properly centred on the arbour.
Ensure rotary tools are dynamically balanced.
Grip the tool handle with the least hand strength practicable
Cover handles with a resilient wrapping layer. Wrapping handles can offer thermal insulation as well as vibration isolation - especially for steel handles.
Wear full-fingered, "antivibration" gloves meeting the requirements of ISO Standard 10819-1996, Mechanical Vibration and Shock - Hand-Arm Vibration - Method for the Measurement and Evaluation of the Vibration Transmissibility of Gloves at the Palm of the Hand.
Replace an old tool with a new tool having lower vibration
Reduce vibration entering the hand by suspending the tool's weight on a balancer
Substitute a process which eliminates or reduces the need for vibrating tools
Control the length of a worker's daily exposure by job rotation.

Control measures to protect against whole-body vibration (WBV) include the following:

Choose a suspended seat containing a vibration-damping mechanism.
Choose a suspended seat adjustable for the worker's weight.
Dynamically balance vehicle wheels.
Fit tires with a low vibration tread pattern.
Regularly grade the surface over which vehicles operate.
Reduce speed when moving over bumpy surfaces.
Avoid sudden load changes (pick up, drop off).
Avoid bumping into obstacles while driving.
Fit vibration-damping mechanisms where possible.
Maintain shock absorbers on vehicles.
Isolate booths/cabs, etc., by setting them on their own separate foundations.
Train workers not to jump in order to exit equipment, particularly from an elevation, as the intervertebral discs may have been softened by the vibrating equipment, jumping can more easily cause shock and damage to the body.

G7.14 Information on adverse effects

Issued January 1, 2005

Section 7.14 of the OHS Regulation states:

The employer must, if a worker is exposed to levels of vibration above the vibration exposure limits, inform the worker of the nature of the hazard and possible adverse effects.

Excessive exposure to hand-arm vibration (HAV) can cause vascular, neurological, and musculoskeletal damage to workers' fingers and hands. The symptoms of hand-arm vibration syndrome (HAVS) include circulatory pain (notably triggered by cold), loss of dexterity, and development of bone cysts and joint abnormalities. Workers may complain of episodes of pale, white fingers often triggered by exposure to cold. It is believed that vibration can adversely affect the blood circulation, making fingers sensitive to the vasoconstriction due to cold. Initially, only the tips of one or more fingers are "blanched," but more segments and fingers are affected with further vibration exposure.

Workers also may experience tingling or numbness in the fingers and hands. With continued exposure, the sensations worsen and can interfere with work and result in the loss of the normal sense of touch. Some vibration-exposed workers (rock drillers, forestry workers) may show signs of carpal tunnel syndrome (CTS) suggesting that vibration can combine with repetitive motion, forceful gripping, and awkward postures (all ergonomic stressors) to contribute to hand and wrist disorders.

Higher occurrences of osteoarthritis in the wrist and elbow have been observed in workers using hand-held, pneumatic percussive tools (miners, construction, metal workers). Workers may also complain of muscular weakness, pain in the hands/arms, and reduced grip strength. In some cases, muscle fatigue can cause disability. Other occupational disorders in vibration-exposed workers include tendonitis and tenosynovitis (inflammation of tendons and their sheaths) in the upper limbs.

Whole-body vibration (WBV) may be associated with an increased risk for low back pain, sciatic pain, and degenerative changes in the spinal column including lumbar intervertebral disc disorders.

For the vibration magnitudes in all but the most severe occupational situations, the adverse health conditions of WBV and HAV may not develop until there has been a prolonged period of time (measured in years) of regular daily exposure.

G7.15 Labels

Issued August 1999; Revised January 1, 2005

Section 7.15 of the OHS Regulation states:

If the manufacturer of equipment that produces levels of vibration in excess of the vibration exposure limit does not label the equipment to identify the hazard, the employer is responsible for doing so.

This section requires that equipment producing levels of vibration in excess of recommended limits be labelled to identify the hazard. Ideally, this label will be permanently affixed by the equipment manufacturer during assembly. In many cases, however, the manufacturer will not have permanently affixed a label identifying the hazard. In these cases, the employer is required to affix the label.

The intent of section 7.15 of the OHS Regulation is to have the employer contact the manufacturer or supplier to obtain a label if one has not already been provided. The intent of section 7.15 is not to require the employer to measure the vibration level of the equipment.

There is no required format for the label. Any means that effectively communicates the vibration hazard is acceptable. For example, the employer could use a symbol instead of words as long as workers are trained to know what the symbol means.

It will be difficult for an employer to securely apply a label to some small pieces of equipment. For example, an adhesive label applied to a chainsaw used in the woods will likely be damaged beyond legibility before long. In such cases, where a label will likely not stay intact on a piece of equipment, it is acceptable for an employer to keep the label in a location where it will not easily be damaged or destroyed. The label is to be kept near the equipment and be readily available to the worker. Acceptable locations include the equipment's storage case or an accompanying operations manual.

Where the label cannot be applied directly to the equipment, workers should receive instruction in the location of the label.

G7.16 Exposure to cold

Issued January 1, 2005

Section 7.16 of the OHS Regulation states:

When a worker is exposed to hand-arm vibration, the employer, to the extent practicable, must ensure that the worker's hands or arms are not exposed to cold, either

(a) from the environment in which the worker is working or as a result of using equipment, or

(b) from coming into contact with cold objects.

Hand-arm vibration can inflict vascular damage to workers' fingers - a condition known as hand-arm vibration syndrome (HAVS). See OHS Guideline G7.14 for further information. To reduce the incidence of HAVS (and the onset of pain for workers who already have HAVS), workers using vibrating tools should keep their hands warm to improve circulation.

Here are some examples of ways for workers to keep their hands warm:

Redirect exhaust air from pneumatic tools away from the hands. Compressed air released from pneumatic tools' exhaust ports has a strong cooling effect as it expands to atmospheric pressure.
Provide dry towels and a change of dry gloves for workers using vibratory tools when their hands may become wet from rain or perspiration.
Insulate handles of vibratory tools in cold environments.

Guidelines Part 7 - Division 3 - Radiation Exposure

G7.17 Definitions - Calculation of the equivalent dose and the effective dose

Issued January 1, 2005

Section 7.17 of the OHS Regulation states:

In this Division:

"action level, ionizing radiation" means an effective dose of 1 milliSievert (mSv) per year;

"action level, non-ionizing radiation" means the exposure limits for the general public referred to in section 7.19(4), or if no public limit is referred to, it means the maximum exposure limit for workers in section 7.19(4);

"effective dose" means the amount of ionizing radiation, measured in mSv, absorbed by the worker's whole body, adjusted for the energy level and type of radiation and the differing susceptibilities of the organs and tissues irradiated, and if only part of the body is exposed the effective dose is the sum of the weighted equivalent doses in all irradiated tissues and organs;

"equivalent dose" means the amount of ionizing radiation, measured in mSv, absorbed by a specific body part and adjusted for the energy level and type of radiation.

The radiation weighting factors (used in determining equivalent dose) and the tissue weighting factors (used in converting equivalent dose to effective dose) are found in ICRP Publication 60, 1990 Recommendations of the International Commission on Radiological Protection, and are included here in Tables 1 and 2.

The equivalent dose (in mSv) is calculated by multiplying the absorbed dose (in milligrays) by the radiation weighting factor (see Table 1). A typical exposure may include more than one type of radiation, and the total equivalent dose is the sum of the components calculated for each type of radiation.

Table 1: Radiation weighting factors

Type of radiation	Radiation weighting factor (W_R)
Photons (e.g., x-rays or gamma) Alpha Neutrons (various energies) Protons	1 20 5, 10, or 20 5

The effective dose (in mSv) is then calculated by multiplying the equivalent dose by the tissue weighting factor (see Table 2) for the part of the body exposed.

Table 2: Tissue weighting factors

Organ or tissue	Tissue weighting factor (W_T)
Gonads (testes or ovaries)	0.2
Red bone marrow; colon; lung; stomach	0.12
Bladder; breast; liver; esophagus; thyroid	0.05
Skin¹; bone surfaces	0.01
All organs and tissues not mentioned above²	0.05
Whole body	1

1. The weighting factor for skin only applies when the whole body is exposed.

2. Hands, feet, or lens of the eye have no tissue weighting factors.

G7.18 Application for ionizing and non-ionizing radiation - Agencies having jurisdiction

Issued August 1999; Revised January 1, 2005

Section 7.18 of the OHS Regulation states:

(1) This Division applies to all sources of ultrasonic energy, non-ionizing and ionizing radiation, including radiation sources governed by the Nuclear Safety and Control Act (Canada), except as otherwise determined by the Board.

(2) This Division does not apply to medical or dental radiation received as a patient, or to natural background radiation, except as specified by the Board.

Agencies having jurisdiction over exposure to radiation include the Workers' Compensation Board (WCB), the Radiation Protection Services (RPS), and the Canadian Nuclear Safety Commission (CNSC). The mandates of these agencies with respect to radiation are briefly described below.

Workers' Compensation Board (WCB) of BC
The WCB administers the OHS Regulation, which includes provisions for protecting workers from exposure to ionizing radiation, electromagnetic fields, lasers, ultraviolet radiation, and ultrasound. The OHS Regulation does not differentiate between ionizing radiation in the form of X-rays or from radioactive sources - the requirements apply equally to both. This differs from the CNSC regulations, which only apply to ionizing radiation from radioactive materials or particle accelerators.

A WCB inspection is not restricted to issues of radiation, but an officer may also check for compliance with the other applicable sections of the OHS Regulation, such as the requirement for an occupational health and safety program.

The WCB officer will normally review a radioisotope licence at the work site in order to determine the nature and quantity of any radioactive materials at the workplace.

Radiation Protection Services (RPS)
RPS is a division of the provincial BC Centre for Disease Control. It works closely with interested parties, including employers, citizens groups, associations, and the general public, on matters of all types of radiation, such as radiofrequency, microwave, ultraviolet, laser, ultrasound, and ionizing radiation, as they pertain to public and worker safety. RPS has substantial expertise and the ability to monitor and problem-solve. It also oversees the diagnostic X-ray unit accreditation process for hospitals and other medical facilities and the "partnership programs" developed with the applicable college or association.

The Internet site for the RPS is http://www.bccdc.org; click on "Divisions" followed by "Radiation Protection Services."

Canadian Nuclear Safety Commission (CNSC)
CNSC, previously known as the Atomic Energy Control Board of Canada, is a federal authority that focuses primarily on the control of the health, safety, and environmental consequences of nuclear activities. CNSC does not have a mandate for X-ray machines or for non-ionizing radiation such as radiofrequency, microwave, or ultraviolet radiation.

The CNSC replaced the Atomic Energy Control Board in May 2000 when the Nuclear Safety and Control Act and its regulations came into effect. The Internet site for CNSC is http://www.nuclearsafety.gc.ca/.

CNSC inspectors perform routine compliance inspections of organizations (referred to as "licensees") that have received a licence from the CNSC to work with radioactive material. The licence will state what isotopes and devices can be possessed, as well as where and how they are to be handled and maintained. The licence will also list the prescribed (for example, radioactive) substances and devices to which the licence applies and may specify a number of conditions with which the licensee is required to comply. These may include conditions with respect to allowable radiation levels, signage, leak tests, dosimetry, disposal, and reporting of accidents.

The CNSC requires that the licence be available at any location where the prescribed substances are used or stored. A CNSC inspector's primary responsibility is to measure compliance with the conditions on the licence and with the regulations, which apply to the handling of radioactive material. These regulations include CNSC Transport Packaging of Radioactive Materials, and Transportation of Dangerous Goods.

A routine inspection entails checking for and ensuring the accuracy of all records, such as inventory, leak tests, dosimetry, training, and shipping documents. Inspectors would also check that the radioactive material is stored properly and that appropriate signs are posted, such as radiation warning signs and contact details. They also check to see that the appropriate monitoring equipment is available and that it is being properly maintained. Similar to the process followed by WCB officers, CNSC inspectors leave a report identifying items of non-compliance and then follow up to ensure compliance is achieved.

CNCS inspectors are also involved in investigating incidents. These investigations can lead to a variety of actions, including the suspension of a licence or prosecution.

G7.19-1 Exposure to ionizing radiation - Exposure limits and exposure period

Issued August 1999; Revised January 1, 2005

Section 7.19(1) and (2) of the OHS Regulation states:

(1) A worker's exposure to ionizing radiation must not exceed any of the following:

(a) an annual effective dose of 20 mSv;

(b) an annual equivalent dose of

(i) 150 mSv to the lens of the eye,

(ii) 500 mSv to the skin, averaged over any 1 cm² area at a nominal depth of 7 mg/cm², regardless of the area exposed, or

(iii) 500 mSv to the hands and feet.

(2) If a worker declares her pregnancy to the employer, her effective dose of ionizing radiation, for the remainder of the pregnancy, from external and internal sources, must be limited by the employer to the lesser of

(a) 4 mSv, or

(b) the dose limit specified for pregnant workers under the Nuclear Safety and Control Act (Canada).
...

Section 7.19(1) provides annual dose limits for all workers exposed to radiation. The time period for measurement is a calendar year, with a start date of January 1, as used by the National Dose Registry (NDR). The NDR administers a centralized radiation dose record system for all radiation workers on a monitoring program in Canada. The NDR is operated by the Radiation Protection Bureau (RPB) of Health Canada. Further information on the National Dose Registry can be found at the Health Canada Internet site at http://www.hc-sc.gc.ca/ewh-semt/pubs/eval/inventory-repertoire/nds_e.html.

Section 7.19(2) provides the dose limits for pregnant workers. The external dose referred to in section 7.19(2) is measured at the abdomen. The time period over which the dose limits apply is the duration of the pregnancy from the date the pregnancy is declared. In order for an employer to ensure that a pregnant worker's dose is limited to the designated exposure limit for the remainder of the pregnancy, the employer needs to know the time period involved, which is from the date the worker declared her pregnancy to the expected date of delivery.

G7.19-2 Notification of worker overexposure to ionizing radiation

Issued August 1999; Revised January 1, 2005

Reports of worker ionizing radiation overexposure (notifications) to the Board may come from an accident investigation report, from the employer, from the National Dose Registry, or by other means. High Exposure Notifications reported by the National Dose Registry are sent to the Radiation Protection Services of the BC Centre for Disease Control, which then forwards a copy to the manager, Occupational Disease Prevention Services (ODPS) of the WCB. In other situations, if an officer receives notification of a worker exceeding the annual dose limit, the officer is required to notify the manager, ODPS, without delay. This applies to both the effective dose and to an equivalent dose to the skin, eyes, or limbs.

The manager, ODPS, may seek input from occupational health physicians and/or radiological medical advisors and will generally forward a request for an incident investigation to the local occupational hygiene officer. This information will be used to help determine the acceptability of the worker's continued employment in the same job category for the remainder of the exposure period (typically the calendar year).

A worker whose annual effective dose exceeds 20 mSv, as noted under section 7.19(1)(a), should be protected from further exposure until:

An investigation is completed into the causes of the overexposure,
Required corrective actions are determined and implemented,and
A medical opinion is given as to the suitability of further work in the occupation during the control period (normally the calendar year).

In deciding the suitability of a worker continuing in the occupation after a reported overexposure, the employer (in conjunction with the Board) should consider factors such as the following:

The reliability and accuracy of the reported result. The thermoluminescent dosimeters (TLDs) used for monitoring the dose of ionizing radiation have an error factor of about 20%. Also, the incident investigation must determine whether the reading is a real dose to the worker (such as the worker being exposed without protective equipment) or if the dosimeter measured a dose to which the worker was not exposed (such as when the TLD is dropped into the x-ray beam).
The magnitude of the dose received. A worker with an annual effective dose exceeding 50 mSv in a year will normally be restricted from working further in the occupation that led to the high dose for the remainder of the control period (normally the calendar year).
The lifetime dose of the worker. This information can be obtained from the National Dose Registry.
The extent of any injury received from the overexposure and the degree of recovery. It is important to establish any adverse health effects associated with the overexposure (usually not present at less than 500-1000 mSv). Even if there is no indication of acute effects, workers should still be informed of the possibility of long-term adverse health effects resulting from this exposure.
Adequacy of control measures implemented by the employer. These may include protective reassignment, implementation of more protective work procedures, and the increased use of dose monitoring and personal protective equipment.

For some dose levels no other special restrictions should be required if the Board is satisfied that the employer is able to adequately control future exposures.

G7.19(4)-1 Exposure to non-ionizing radiation - Electromagnetic fields

Issued August 1999; Revised January 1, 2005

Section 7.19(4)(a) of the OHS Regulation states:

(4) The employer must ensure that a worker's exposure to non-ionizing radiation does not exceed the exposure limits specified in

(a) for radiofrequency:

(i) Health Canada Safety Code 25, Short-Wave Diathermy Guidelines for Limiting Radiofrequency Exposure, 1983, as amended from time to time;

(ii) Health Canada Safety Code 26, Guidelines on Exposure to Electromagnetic Fields from Magnetic Resonance Clinical Systems, 1987, as amended from time to time;

(iii) Health Canada Safety Code 6, Limits of Human Exposure to Radiofrequency Electromagnetic Fields in the Frequency Range from 3 kHz to 300 GHz, 1999, as amended from time to time, and ...

except as otherwise determined by the Board.

Section 7.19(4)(a) refers to Health Canada's Safety Codes. These three Safety Codes are available on the Health Canada web site:
http://www.hc-sc.gc.ca/ewh-semt/pubs/radiation/index_e.html.

Radiofrequency is defined as the portion of the electromagnetic spectrum that is between 3 kHz and 300 GHz. This definition includes microwaves, radio, and radar.

Safety Code 6 presents two sets of exposure limits for field strength, power density, and induced (contact) currents. Specifically, exposure limits are provided for two groups:

Radiofrequency (RF) and microwave exposed workers - see Table 1 of this guideline
Other individuals, including the general public - see Table 2 of this guideline.

RF workers are employees or persons (including a pregnant woman) who because of his/her knowledge, training and experience with RF devices is qualified to work with these devices properly and safely with respect to RF exposure. Examples of workers who may be in this category include microwave technicians, am/fm radio and TV technicians, antenna crews, transmission tower maintenance workers, RF sealer/heater operators, radar technicians, physiotherapists using short wave diathermy, and police officers (traffic).

Radiofrequency (RF) and microwave exposed workers are persons who are exposed to RF fields and microwaves in the course of their daily work. Examples of workers who may be in this category include roofers, window cleaners, HVAC system technicians, who may, on occasion, need to perform their regular work near an RF transmitter (but are not RF workers).

General public includes all persons not employed as RF and microwave exposed workers or those not working in controlled environments (areas). They include pregnant women, the aged, children, the chronically ill, and disabled.

Table 1: Exposure limits for RF and microwave exposed workers for radiofrequency electromagnetic fields

Frequency	Electric field strength rms (V/m)	Magnetic field strength rms (A/m)	Power density (W/m²)	Averaging time (min.)
3 kHz - 1 MHz	600	4.9	-	6
1 MHz - 10 MHz	600/f	4.9/f	-	6
10 MHz - 30 MHz	60	4.9/f	-	6
30 MHz - 300 MHz	60	0.163	10*	6
300 MHz - 1.5 GHz	3.54 f ^0.5	0.0094 f ^0.5	f/30	6
1.5 GHz - 15 GHz	137	0.364	50	6
15 GHz - 150 GHz	137	0.364	50	616 000/f^1.2
150 GHz - 300 GHz	0.354 f ^0.5	9.4 x 10^-4f ^0.5	3.33 x 10^-4f	616 000/f^1.2

Source: Table 1, Safety Code 6
* Power density limit is applicable at frequencies greater than 100 MHz.
kHz = kilohertz; MHz = megahertz; GHz = gigahertz
rms (V/m) = root mean square, volts per metre
rms (A/m) = root mean square, amperes per metre
W/m² = watts per square metre
f = frequency in MHz

Note:
Power density of 10 W/m² = 1 mW/cm²
Magnetic Field Strength of 1 A/m = 1.257 microtesla (µT) or 12.57 milligauss (mG).

The action level for radiofrequency (non-ionizing) radiation is defined in section 7.17 of the OHS Regulation as the exposure limit for the general public. The applicable table in Safety Code 6 is the table of exposure limits for persons other than RF workers. These are given in the following table.

Table 2: Exposure limits for persons not classified as RF and microwave exposed workers (including the general public)

Frequency	Electric field strength rms (V/m)	Magnetic field strength rms (A/m)	Power density W/m²	Averaging time (min.)
3 kHz - 1 MHz	280	2.19	-	6
1 MHz - 10 MHz	280/f	2.19/f	-	6
10 MHz - 30 MHz	28	2.19/f	-	6
30 MHz - 300 MHz	28	0.073	2*	6
300 MHz - 1.5 GHz	1.585 f ^0.5	0.0042 f ^0.5	f/150	6
1.5 GHz - 15 GHz	61.4	0.163	10	6
15 GHz - 150 GHz	61.4	0.163	10	616 000 f^1.2
150 GHz - 300 GHz	0.158 f ^0.5	4.21 x 10^-4f ^0.5	6.67 x 10^-5f	616 000 f^1.2

Source: Table 5, Safety Code 6
* Power density limit is applicable at frequencies greater than 100 MHz.
kHz = kilohertz; MHz = megahertz; GHz = gigahertz
rms (V/m) = root mean square, volts per metre
rms (A/m) = root mean square, amperes per metre
W/m² = watts per square metre
f = frequency in MHz

Note:
Power density of 10 W/m² = 1 mW/cm²
Magnetic Field Strength of 1 A/m = 1.257 microtesla (µT) or 12.57 milligauss (mG).

G7.19(4)-2 Exposure to non-ionizing radiation - Lasers

Issued August 1999; Revised January 1, 2005

Section 7.19(4)(b) of the OHS Regulation states:

(4) The employer must ensure that a worker's exposure to non-ionizing radiation does not exceed the exposure limits specified in
...

(b) for lasers:

(i) ANSI Standard Z136.1-2000, Safe Use of Lasers, as amended from time to time;

(ii) ANSI Standard Z136.2-1997, Safe Use of Optical Fiber Communication Systems Utilizing Laser Diode and LED Source, as amended from time to time;

(iii) ANSI Standard Z136.3-1996, Safe Use of Lasers in Health Care Facilities, as amended from time to time;

(iv) CSA Standard Z386-01, Laser Safety in Health Care Facilities, as amended from time to time,

except as otherwise determined by the Board.

Section 7.19(4) refers to applicable ANSI and CSA standards. CSA Standard Z386-01 is a reproduction of ANSI Standard Z136.3 but with a few pages of "Canadian Deviations," which make the standard more applicable to the health care environment in Canada.

The determination of worker exposure to non-ionizing radiation from lasers is very complex. Calculation of the exposure limit is dependent on the type of laser being assessed; there is no generic calculation covering all laser sources. Neither a WCB officer nor an employer would normally be expected to measure the radiation being emitted by a laser. Rather, compliance with this section will normally be determined by an evaluation of the laser safety program, as required by the applicable standard - such as the program outlined in Table 10 of ANSI Standard Z136.1-2000. In this instance, an effective laser safety program is equivalent to an effective exposure control plan, and both are equivalent to actually measuring exposures. In other words, workers cannot be overexposed to laser radiation if there is an effective laser safety program in place.

The employer should establish and maintain an adequate program for the control of laser hazards to the eyes and skin. For class 2 and 3a lasers and laser systems, a laser safety program meeting the requirements of ANSI Standard Z136.1-2000, or a program providing an equivalent level of worker protection, constitutes an effective exposure control plan. For class 3b and 4 lasers and laser systems, a laser safety program meeting the requirements of ANSI Standard Z136.1-2000 constitutes an effective exposure control plan. The requirements of a laser safety program are summarized in Table 10 of ANSI Standard Z136.1-2000.

G7.19(5) Exposure to non-ionizing radiation - Ultraviolet radiation

Issued August 1999; Revised January 1, 2005

Section 7.19(5) of the OHS Regulation states:

A worker's exposure to ultraviolet radiation produced by equipment or industrial processes must not exceed the threshold limit values specified in the American Conference of Governmental Industrial Hygienists publication entitled Threshold Limit Values and Biological Exposure Indices, dated 2003, as amended from time to time.

Ultraviolet radiation from the sun is not included within the scope of this requirement. Nevertheless, workers and employers should be aware of the hazards associated with solar radiation. Effective means to limit worker exposure include wearing appropriate dress and the use of sun-block creams.

The American Conference of Governmental Industrial Hygienists (ACGIH) requires that the threshold limit values (TLVs) be applied to sources which subtend an angle of less than 80 degrees at the measuring instrument's detector (i.e., the source subtends less than an 80 degree cone with its vertex at the detector). Most industrial sources, such as lamps or welding arcs, subtend a much smaller arc, so the angular restriction does not apply to them. In these cases, the measurements are simply carried out with the detector at the position of the worker's eye or skin, and no further angular considerations are required.

This restriction becomes important when there is exposure to an extended source, such as a tanning bed, or solar exposure at a sandy beach, in snow, or from another large reflective surface. In these situations, ACGIH prescribes that only the contributions within an 80-degree cone be considered. The reason for this is a practical one. Most instruments use interference filters on their detectors and these filters are inaccurate at large angles. The ultraviolet radiation from large angles contributes little to the effect on the eyes or skin because of geometric and physiological considerations.

G7.20(1)-1 Exposure control plan - General requirements

Issued August 1999; Revised January 1, 2005

Section 7.20(1) of the OHS Regulation states:

If a worker exceeds or may exceed an action level, ionizing radiation or action level, non-ionizing radiation, the employer must develop and implement an exposure control plan meeting the requirements of section 5.54(2).

An exposure control plan is not required if the employer can demonstrate that workers' exposures will not exceed the applicable action level. This guideline discusses ways to determine if a worker's exposure does not exceed the action level for both ionizing and non-ionizing radiation - situations where the employer would not be required to implement an exposure control plan. For further information on exposure control plans, see OHS Guideline G5.54-1.

Ionizing radiation
The action level for ionizing radiation is defined in section 7.17 of the OHS Regulation as "an effective dose of 1 milliSievert (mSv) per year." To determine if this action level is being exceeded or may be exceeded, the employer should consult the annual Report on Occupational Radiation Exposures in Canada, published by the Radiation Protection Bureau of Health Canada, available on the Internet at:
http://www.hc-sc.gc.ca/ewh-semt/alt_formats/hecs-sesc/pdf/pubs/occup-travail/2004-report-rapport_e.pdf

An exposure control plan would not be required if the average annual dose for a Canadian worker in the job sector and category is listed in the Health Canada report showing an exposure is less than 1.0 mSv per year, as an average value over the most recently reported five years. Note there is a statistical spread of annual exposures for each job category. Even if the average annual dose for a job sector is less than 1.0 mSv, a portion of the population may accumulate doses greater than 1.0 mSv. Therefore, if an employer's work practices or conditions are less protective or more hazardous than those anticipated by standards acceptable to the Board, then the employer should implement an exposure control plan.

For jobs not listed in the Health Canada report, the employer may use existing monitoring data from another employer (provided that the workplaces are equivalent in terms of the potential for exposure). An exposure control plan would not be required if this data demonstrates that the exposures result in an effective annual dose less than 1.0 mSv.

Non-ionizing radiation
The action level for non-ionizing radiation is defined in section 7.17 of the OHS Regulation as "the exposure limits for the general public referred to in section 7.19(4), or if no public limit is referred to, it means the maximum exposure limit for workers referred to in section 7.19(4)."

The Board accepts that an exposure control plan is not required if any one of the following conditions is met:

Equipment capable of emitting non-ionizing radiation is being used according to the manufacturer's instructions; and monitoring of field strengths, power densities, irradiance levels, radiant intensities, or ultrasonic sound pressure levels shows that these values cannot exceed the action level in the course of a worker's regular duties.
Documentation from the equipment manufacturer shows that exposures cannot exceed the action level.
For lasers, the class of the laser or laser system is less than class 3, as defined in the latest edition of ANSI Standard Z136.1, Safe Use of Lasers.

G7.20(1)-2 Exposure control plan - Control measures

Issued August 1999; Revised January 1, 2005

Section 7.20(1) of the OHS Regulation states:

If a worker exceeds or may exceed an action level, ionizing radiation or action level, non-ionizing radiation, the employer must develop and implement an exposure control plan meeting the requirements of section 5.54(2).

Section 7.20(1) requires an exposure control plan if a worker's level of exposure exceeds or may exceed the applicable action level. For both ionizing and non-ionizing radiation, adequate engineering and administrative control measures, as specified in the applicable Safety Code or Standard, must be in place in order to control the radiation dose received by any worker to less than the action level. Applying these control measures ensures that the requirements for an exposure control plan are met. Note that under section 5.54(2)(b) of the OHS Regulation, control measures are a required element of an exposure control plan.

In assessing the adequacy of control measures for ionizing radiation, the employer is to use all available exposure information (from personal dosimetry and radiation surveys) to compare the effectiveness of the controls with controls in similar industry facilities. If there is an indication of a single high-exposure situation (for one or more workers), a radiation survey under section 7.24(c) of the OHS Regulation applies.

When reviewing the results of personal dosimetry, the employer will compare the exposure information with workers in similar groups. If there is a significantly higher dose profile than the industry averages indicate is achievable, the employer is to examine the work practices and other conditions of exposure at the workplace, and alter them to reduce the unusually high doses to the acceptable levels as per section 7.19(3). Data from the National Dose Registry (published annually by Health Canada) is available for the purpose of reviewing worker exposure information.

It should also be noted that section 7.19(3) of the OHS Regulation states the "ALARA" principle: "The employer must ensure that the exposure of workers to ionizing radiation is kept as low as reasonably achievable below the exposure limits." For the purposes of section 7.19(3), an employer whose operation demonstrates a significantly higher dose profile than the industry average is expected to reduce worker exposure to the industry average, as that would be considered "reasonably achievable."

G7.20(1)-3 Exposure control plan - Personal protective equipment

Issued August 1999; Revised January 1, 2005

Section 7.20(1) of the OHS Regulation states:

If a worker exceeds or may exceed an action level, ionizing radiation or action level, non-ionizing radiation, the employer must develop and implement an exposure control plan meeting the requ

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Guidelines Part 7

Guidelines Part 7 Contents

DIVISION 1 - NOISE EXPOSURE

DIVISION 2 - VIBRATION EXPOSURE

DIVISION 3 - RADIATION EXPOSURE

DIVISION 4 - THERMAL EXPOSURE

Heat Exposure

Cold Exposure

Guidelines Part 7 - Division 1 - Noise Exposure

G7.2 Exposure limits

G7.3-1 Noise measurement - When required and performance

G7.3-2 Noise exposure data collected by prevention officers

G7.4 Exemption

G7.5-1 Program - Education and training

G7.5-2 Annual program review

G7.6-1 Investigating controls

G7.6-2 Implementing controls

G7.7-1 Selection of hearing protection

G7.7-2 Warning signs and hearing protection

G7.8-1 Annual hearing tests

G7.8-2 Authorized hearing testers

G7.8-3 Hearing test results

G7.8-4 Construction industry

G7.9 Test records

Guidelines Part 7 - Division 2 - Vibration Exposure

G7.11-1 Exposure limits - hand-arm vibration

G7.11-2 Exposure limits - whole-body vibration

G7.12 Evaluation

G7.13 Exposure control plan

G7.14 Information on adverse effects

G7.15 Labels

G7.16 Exposure to cold

Guidelines Part 7 - Division 3 - Radiation Exposure

G7.17 Definitions - Calculation of the equivalent dose and the effective dose

G7.18 Application for ionizing and non-ionizing radiation - Agencies having jurisdiction

G7.19-1 Exposure to ionizing radiation - Exposure limits and exposure period

G7.19-2 Notification of worker overexposure to ionizing radiation

G7.19(4)-1 Exposure to non-ionizing radiation - Electromagnetic fields

G7.19(4)-2 Exposure to non-ionizing radiation - Lasers

G7.19(5) Exposure to non-ionizing radiation - Ultraviolet radiation

G7.20(1)-1 Exposure control plan - General requirements

G7.20(1)-2 Exposure control plan - Control measures

G7.20(1)-3 Exposure control plan - Personal protective equipment