INDOOR AIR QUALITY

 

Click on any of the following links for detailed information.

 

·       OCCUPATIONAL EXPOSURE LIMITS

·       WORKPLACE MONITORING

·       EXPOSURE CONTROL PLAN

·       VENTILATION

Ø    Local exhaust

Ø    Inspection

Ø    Make-up air

Ø    Design

Ø    Maintenance

·       INVESTIGATION

·       SMOKING

 

OCCUPATIONAL EXPOSURE LIMITS

Worker exposure to a hazardous substance must not exceed the exposure limits specified in the Table of Exposure Limits for Chemical and Biological Substances. The chart below is excerpted from the table, and contains some common hazardous substances and their exposure limits. Ceiling refers to the maximum amount a person may be exposed to at any time.

 

Chemical name

8-hour

exposure limit

15-minute

exposure limit

Notes

Acetic acid

10 ppm

15 ppm

--

Acetone

250 ppm

500 ppm

--

Ammonia

25 ppm

35 ppm

--

Carbon black

3.5 mg/m3

 

Considered to be a carcinogen

Carbon dioxide

5,000 ppm

15,000 ppm

--

Carbon monoxide

25 ppm

100 ppm

Considered to have a reproductive health effect

Ethyl acetate

150 ppm

--

--

Formaldehyde

0.3 ppm

--

1 ppm ceiling

Hydrogen sulfide

--

--

10 ppm ceiling

Hydroquinone

--

--

2 mg/m3 ceiling

Isopropyl alcohol

200 ppm

400 ppm

--

Sulfur dioxide

2 ppm

5 ppm

--

 

If a worker is exposed to two or more substances, the exposure is additive. (Occupational Health and Safety Regulation 296/97, 5.48 – 5.51)

 

WORKPLACE MONITORING

A walkthrough survey of the workplace must be completed to assess the potential for worker overexposure. The workplace must be reassessed whenever there is change in work conditions.

 

If the assessment indicates that worker exposure may exceed 50 percent of the exposure limit, additional monitoring must be completed to quantify the exposure. Results of the assessment must be provided to workers. (Occupational Health and Safety Regulation 296/97, 5.53)

 

EXPOSURE CONTROL PLAN

An exposure control plan must be implemented when a worker is exposed to greater than 50 percent of the exposure limit. The plan must contain the following elements: the purpose of the plan and responsibilities, identification of the risk, assessment of the risk and means to control it, and education and training. When required, the plan must contain the following additional elements: written work procedures, hygiene facilities, health monitoring, and documentation.

 

The plan must be reviewed annually in consultation with the JHSC. (Occupational Health and Safety Regulation 296/97, 5.54)

 

VENTILATION

Local exhaust

The worker’s breathing zone must not be located between the contaminant source and the exhaust. (Occupational Health and Safety Regulation 296/97, 5.65)

 

Inspection

An exhaust ventilation system must be inspected and monitored to ensure that it is effective. (Occupational Health and Safety Regulation 296/97, 5.67)

 

Make-up air

Make-up air must be provided to maintain an effective exhaust system and to prevent air contaminants from being drawn into the work area. Make-up air must not create uncomfortable temperatures or drafts.

 

Recirculated discharged air must not contain contaminants with a concentration of more than 10 percent of the exposure limit and must not create an objectionable odour. (Occupational Health and Safety Regulation 296/97, 5.69)

 

Design

The ventilation system must be designed, constructed and operated according to established engineering principles and in accordance with ASHRAE standard 62-1989, Ventilation for Acceptable Indoor Air Quality.

 

Adequate outdoor air must be supplied in accordance with table 2 of the ASHRAE standard. The outdoor air must be distributed throughout the workplace and the system must be balanced. (Occupational Health and Safety Regulation 296/97, 4.72)

 

Maintenance

An effective preventive maintenance program must be established for the ventilation system. The program must include the following elements: inspections, corrective actions, repairs, treatment of open water systems, and maintenance of combustion sources. (Occupational Health and Safety Regulation 296/97, 4.78)

 

INVESTIGATION

An indoor air quality investigation must be conducted whenever complaints are received, there are changes in occupancy, or renovations to the facility. The investigation must include an assessment of the ventilation rate, an inspection of the system, sampling for contaminants, and retention of records. (Occupational Health and Safety Regulation 296/97, 4.79)

 

SMOKING

Exposure to smoke must be controlled by prohibiting smoking or restricting it to a designated area. 

 

A designated smoking area must be identified, in a separate room or outdoors. If necessary, the designated smoking area must be equipped with an exhaust system. (Occupational Health and Safety Regulation 296/97, 4.81 – 4.82)

 

Check local bylaws to determine whether there are any municipal smoking regulations.

 

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