Occupancy limits are set as per floor space area rather than ACH. Generally, you would want to give ~5 square meters of unencumbered floor space per person to establish occupancy limits. The BC Building Code dictates the determination of occupancy limits. See this link: https://www2.gov.bc.ca/gov/content/safety/emergency-preparedness-response-recovery/fire-safety/legislation-regulations-codes/occupant-load. As specified in the Industrial Ventilation — A Manual of Recommended Practice, "Air changes per hour" or "air changes per minute" is a poor basis for ventilation criteria where environmental control of hazards, heat, and/or odors is required. Air changes per hour are calculated by taking the supply airflow into the room (in units of cubic feet/min) times 60, and divided by the volume of the room. Occupancy limits are set accordingly with the area of the room, as well as intended use of the room. See attached PDF for this formula to determine relationship between ACH and Occupancy limit. From the numbers that provided, further information is needed for the calculation (Area of the room and acceptable area/person).
Ask Me Anything about air quality at work
May 4th, 2021 11:00-12:00PM
*Cough* *Cough* What’s that smell? What am I breathing in? In this Ask Me Anything Session, we will dive into the world of air quality and go over the basic principles surrounding it, so you can better identify or categorize hazards in your workplace. Don’t forget to bring your questions!
We look forward to seeing you at these FREE sessions and hope we can answer your questions about workplace health and safety.
These are LIVE sessions—audience engagement is strongly encouraged. You will have the opportunity to ask questions through chat.
In this webinar you will learn
- Anything and everything you’ve always wanted to ask about air quality
- Health and safety impact of air quality
- Common causes of air quality problems in the workplace
- Signs and symptoms of poor air quality
Webinar Q&A
KN95 is considered to be the equivalent to the US NIOSH N95, in terms of filter performance as outlined in the 3M document and other N95 alternatives for counties. KN95 are also recognized by WorkSafeBC in being the equivalent to N95. The KN95 just follows a different certification process, i.e. GB2626-2006, vs the N95 (NIOSH - 42C FR84).
Particulate disposable respirators often times have a nuisance odor relief feature. These respirators are for protection against particulate matter, however, if for context of smell these types of respirators may assist for the odor relief. Check out this link: https://www.3m.com/3M/en_US/p/c/ppe/respiratory-protection/disposable/i/safety/personal-safety/
To determine the concentration of a contaminant in the air, specialized equipment is needed for this assessment. Typically, air sampling pumps and/or specialized media is put on a worker for the duration of the shift (or a representative time). This media is then sent off to a lab for analysis, and a report is generated indicating the concentration a worker is exposed to during the sampled time. Comparison is then made with the regulatory exposure limits. Other means of assessment also involve using direct reading instruments. With this, we are able to get a concentration in that moment, and it does not require the sample to be sent off to a lab for further analysis. These would be, in simplest terms, the way to truly determine contaminant concentrations.
