In NFPA 70 (National Electrical Code / NEC), the use of a Combustible Gas Detection System (CGDS) is a highly specialized engineering provision. It essentially acts as a “get out of jail free” card—or more accurately, a reclassification tool—for specific industrial locations. When you install a qualified CGDS, the NEC allows you to lower the electrical classification of an area (e.g., from Division 1 to Division 2, or from Division 2 to Unclassified), which drastically reduces the cost and complexity of the electrical equipment you are permitted to install.
Two (2) major limitations we will discuss:
- A facility cannot simply buy an off-the-shelf gas detector, screw it to the wall, and declare a room unclassified.
- Portable, hand-held gas detectors do NOT satisfy the code.