Confined Space Atmospheric Testing

Before and during entry into a confined space, atmospheric testing must be performed. The attendant must test the space prior to entry, and the authorized entrant must test the space often during entry. This is a routine part of the entry process that helps determine appropriate control measures.

According to 1910.146(c)(5)(ii)(B), the appropriate method when conducting atmospheric testing it to test for oxygen levels first, combustible levels second, and toxin levels third.

Ventilation

Ventilation is the main control for hazardous atmospheres. Ventilation can be provided by dilution ventilation or exhaust ventilation. Both types of ventilation are used to reduce concentrations of flammable and toxic fumes or particulates. Examples of dilution ventilation include grounded air movers powered by compress air, electric fans and blowers, and natural ventilation. Examples of exhaust ventilation include electric ducted fans and blowers, electric non-ducted fans and blowers, and an air ejector operated by compressed air.

Retesting

Retesting and continuous monitoring of air is necessary throughout the entry process. If a worker leaves a confined space for a short amount of time the confined space must be retested before the worker reenters.

To learn more visit our Confined Space Online Training web page.