Committee Moves Quickly on Gas Purging Change
Acting in response to the U.S. Chemical Safety Board's recommendations from the ConAgra Slim Jim explosion, NFPA's National Fuel Gas Code Committee proposed an emergency change to strengthen NFPA 54. Expedited public review and comment will follow.
Before last month's Kleen Energy explosion turned even more attention to gas purging practices, the U.S. Chemical Safety Board had issued urgent recommendations about gas purging after investigating the ConAgra Slim Jim explosion last June in North Carolina. In response, NFPA's National Fuel Gas Code Committee has made an emergency change to strengthen NFPA 54, the National Fuel Gas Code. Expedited public review and comment will follow.
The committee met Feb. 23-25 and initiated a Tentative Interim Amendment (TIA) to change the code's current edition on an emergency basis. The proposed change requires gas purging to be discharged outdoors with these specific requirements to be met:
1. The point of discharge shall be controlled with a shutoff valve.
2. The discharge point shall be at least 10 feet from sources of ignition, at least 10 feet from building openings, and at least 25 feet from mechanical air intake openings.
3. During discharge, the open discharge point shall be continuously attended and monitored with a combustible gas indicator.
4. Purging operations introducing fuel gas shall be stopped when 90 percent fuel gas by volume is detected within the pipe at the point of discharge.
5. All persons not involved in the purging operations shall be evacuated from the area within 25 feet of the discharge point.
NFPA said there will now be a letter ballot of the Technical Committee and an expedited public review and comment period on the TIA, which allows lessons learned from the CSB investigation at ConAgra to be implemented without waiting for the 2012 edition of NFPA 54 to be completed.