Atmospheric testing is a critical step in identifying and managing hazardous conditions in the workplace. Whether it’s detecting toxic gases, low oxygen levels, or flammable vapors, proper testing helps protect workers from invisible threats that could lead to serious injuries or worse.
Evaluation Testing
The atmosphere within a confined space must be tested using equipment capable of detecting hazardous substances at concentrations below the applicable exposure limits established by OSHA. Evaluation testing is conducted to identify potential atmospheric hazards and determine the necessary steps to ensure safe entry conditions.
Atmospheric Hazards
Before entering a confined space, it’s important to understand the types of atmospheric hazards that may be present, such as:
- Oxygen deficiencies
- Dust
- Chemical vapors
- Welding fumes
- Or, fogs or mists interfering with the body’s ability to transport and utilize oxygen
Verification Testing
Before entering a potentially hazardous permit-required space, the atmosphere must be tested according to procedures outlined on the permit, which are established during the evaluation process. This testing verifies chemical hazards are below safe levels and meet permit conditions.
OSHA requires conducting verification testing in a specific order: first test for oxygen, then combustible gases, followed by toxic gases and vapors.
Record the actual concentrations measured in the test results and document them on the permit next to the acceptable entry levels.
Duration of Testing
Allow enough time for the equipment to sample the air and sensors to detect chemicals for each required test. The manufacturer typically defines this as the ‘minimum response time’ and notes it in the operator’s manual.
Add extra time to the response time when using a hose or probe extension to allow air from different depths to reach the inlet.
Regularly test permit spaces to verify that atmospheric conditions remain safe for entry.
Layered Atmospheres
In deep or extended permit spaces, the atmosphere may vary or layered. Test the air around the worker, extending 4 feet ahead and to each side.
When using a sample probe, workers must move slowly, allowing time for testing based on the equipment’s response time before entering a new area.
Conclusion
Atmospheric testing is a vital component of workplace safety, especially when working in or around confined spaces. Accurate detection of gases and oxygen levels protects workers from invisible, potentially deadly threats.