Explosion proof lights are subject to rigorous testing, to ensure certain safety standards and guidelines are met accordingly. Conducted by a Nationally Recognized Testing Laboratory (NRTL), this aspect of explosion proof compliance is closely tied with several OSHA regulations pertaining to products that require approval from a recognized third-party establishment.
OSHA and NRTL
To understand how NRTL testing for explosion proof lights work, it is important to first trace the origin of such salient requirements. In 1988, OSHA published and implemented NRTL guidelines (29 CFR 1910.7). A NRTL is a private, third-party establishment that has been approved by OSHA to conduct tests and certification on specific products, based on existing standards.
In this process, OSHA can be viewed as a ‘governing body’ that facilitates the NRTL testing program. OSHA does not conduct testing for explosion proof lights. The organization, however, recognizes a set of NRTLs that performs tests for explosion proof compliance and other products requiring marks from recognized labs, such as the following:
- Intertek Testing Services (ETL)
- FM Approvals LLC (FM)
- Nemko North America (NNA)
- Underwriters Laboratories (UL)
- CSA Group Testing and Certification (CSA)
*Not complete list
Who Makes the Standards? (Standard vs Lab)
NRTLs do not make the regulations; their primary role (as a testing lab) is to ensure certain standards are effectively met through testing and certification. The safety standards are created by a different group, such as UL, ASTM and ASME. Based on this relationship, a product can bear an ETL marking (for example), which ensures compliance with specific UL standards the unit was tested for.
Example scenario: A manufacturer seeks compliance with UL 844 (Standard for Luminaries for use in Hazardous [Classified] Locations) for a portable or fixed mount explosion proof light to be installed in a Hazardous (Classified) location. In this case, UL 844 is a standard created by UL. An example of a live product that exceeds the requirements of UL 783 is the Larson Electronics Explosion Proof LED Light (EPL-HB-150LED-RT).
For the certification process, the US-based manufacturer may approach an NRTL that is approved by OSHA and capable of testing for the UL 844 Standard.
Let’s say the manufacturer has selected ETL (a division of Intertek) as the NRTL that will perform the certification process. According to OSHA, UL 844 is a recognized testing standard by Intertek, further implying that the lab is capable of certifying products in compliance with UL 844.
ETL then moves forward and completes the required tests. Upon passing the inspections, ETL provides a mark and certifies the product for compliance with UL 844.