StacksVerified U.S. regulatory reference

30 CFR §18.98

Verified against eCFR.gov as of June 20, 2026View official text on eCFR.gov ↗
  1. (a)Cast or welded enclosures shall be designed to withstand a minimum internal pressure of 150 pounds per square inch (gage). Castings shall be free from blowholes.
  2. (b)Pneumatic field testing of explosion-proof enclosures shall be conducted by determining:
    1. (1)Leak performance with a peak dynamic or static pressure of 150 pounds per square inch (gage); or
    2. (2)A pressure rise and rate of decay consistent with unyielding components during a pressure-time history as derived from a series of oscillograms.
  3. (c)Welded joints forming an enclosure shall have continuous gastight welds.