Occupational Exposure Limit (OEL,PEL,TLV)

       In the field of occupational hygiene there are many limits that have to be set in place to ensure the safety of employees in the workplace. These occupational exposure limits vary for different substances. These different substances that could harm your health could be gasses,vapors or aerosols which could be dust, fibers, smoke, etc. The limits OEL's or PEL's were set in place after the 1970 occupational safety and health act. Other standards that were adopted by OSHA  were the 1968 threshold limit values, also known as TLV's  which were put in place by the American Conference of Governmental Industrial Hygienists. OSHA has set these limits based on 8 hour work days and 40 hour work weeks. These increments are calculated by the time weighted average or also referred to as TLV. OEL's are calculated as parts per million (ppm) and then converted to milligrams per cubic meter. These values could also be represented as ceiling values, short term exposure limits which are usually around 15 minutes of exposure, and IDLH which stands for immediately dangerous to life or health. Short term exposure limits (STEL) are limits where workers can be exposed for short intervals without suffering. The ceiling value is a concentration that should not be exceeded at any point during the workday and is represented with a C. This C comes after the substance listing.  There are many problems with OSHA's enforcement of PEL's and TLV's in the workplace due to the outdated limits that were set almost 43 years ago. OSHA tried to adopt new limits in 1989 but due to many complications they dropped the newly found limits and continued to use the old limits adopted in 1971. The people in charge of recommending occupational exposure limits now is the National Institute for Occupational Safety and Health. This institute has recommended exposure levels for around 700 substances to this day.

OSHA
PEL and TLV

The first device has a pump and shows how much air is coming in and the second device is a cyclone and collects the contaminants in the air.