Anyone who works at a business that has a formal hotwork program can recite the distance at which all fire safety requirements must be in place… 35′. But this 35′ is a “magical number” to many who use it on a daily basis. Don’t believe the number is “magical”? Just go out and ask your permit approvers or your welders why the “35′ rule” is not the “25′ rule” or the “45′ rule”. Before reading this article, could you explain to your management and workers why 1910.252(a), NFPA 51B, and FM Global’s Data Sheet 10-3 uses 35′ for the fire safe area? Here is the explanation of the 35′ rule and some other helpful Hotwork safety information.
If you have access to FM Global’s Hot Work DVD – GET IT and watch it. The mystery will be answered as to why the fire safe area is to be 35′ and not 25′ or 45′. It is all based on, and this is demonstrated in the DVD, that a worker doing work from a traditional 6′ step ladder the sparks will bounce across the floor up to 35′. But I should also point out that both NFPA 51B and FM Global’s Data Sheet 10-3 contain ADDITIONAL REQUIREMENTS when hotwork is done from an “elevated” position.
FM Global’s Data Sheet 10-3
3.1.4 Elevated Hot Work
For elevated hot work, combustible materials should be either relocated a minimum of 50 ft (15.2 m) from the hot work area; or properly protected with fire retardant welding blankets; or the hot work operation isolated with welding screens. Suspend fire-resistive welding blankets under hot work conducted near the ceiling. Place noncombustible screens around hot work at the floor to trap sparks. Every elevated hot work operation needs to be evaluated on a case-by-case basis to determine a reasonable safe distance from hot work to combustible occupancies or construction. The physical conditions involved may dictate relocation of combustibles beyond 50 ft (15.2 m).
NFPA 51B
5.4* Hot Work Permit
(14)*In instances where the scope of work and the tools used to conduct hot work result in possible travel of slag, sparks, spatter or similar mobile sources of ignition farther than 35 ft (11 m), the PAI shall be permitted to extend the distances and areas addressed in 5.4.2(2) through 5.4.2(4).
Some interesting and updated Hotwork Data from NFPA and FM Global
1) Cutting and welding is the most dangerous:
- Account for 5% fires, 10% of property damage
- Most fires around lunch, breaks, and shift change
- 1/3 of fire involved structural members and/or insulation
- Contractors involved in 67% of the hotwork fires
- Most of the fires start in designated hotwork areas
2) FM Data on Incidents Relating to “Time After Hotwork”
Time Frame % of Fires/Explosions
≤ 30 Min. 33
> 30 Min. ≤ 60 Min. 15
> 60 Min. ≤ 4 Hrs 21
> 4 Hrs 31
3) FM Global studied 600 of its clients’ hot work losses over a 10 year period and found:
- $750 million in property loss
- $1.3 million per fire
- Almost 90% due to poor hot work safety guidelines
- Incomplete loss prevention procedures
- Personnel not following management’s guidelines
- Untrained personnel or unsupervised contractors
- Weak or out-of-date policies
4) The United States averages 12,630 hot work fires, $308.9 million in property damages and 31 deaths per year (Source: University of Iowa)
Designated Hot Work Areas
An interesting move by the NFPA 51B Committee to address what is a VERY COMMON hotwork safety issue… designated hotwork areas are NOT fire safe! We have seen just about everything when it comes to “designated hotwork areas”. These are areas that OSHA, NFPA and FM Global allow the work to be taken to and the hotwork can be done WITHOUT a hotwork permit and fire watch; however, the basic premis for this exception is that the “designated area” is SAFE for hotwork! We have seen “designated hotwork areas” next to propane storage, cylinder storage, flammable and combustible liquid storage, HVAC filters storage, etc. So apparently the NFPA committee members are seeing the same concerns and this month (October 2012) proposed the following additions to NFPA 51B…
Proposed Requirements for Designated Area:
5.2.2.1 Designated Areas.
5.2.2.1.1 In order for a location to be a designated area, a risk assessment shall be performed.
5.2.2.1.2 The designated area shall meet the requirements in section 5.4.2.
5.2.2.1.3 The risk assessment for a designated area shall be reviewed at least annually.
5.2.2.1.4 Prior to the start of any hot work in a designated area, the hot work operator shall perform the following:
(a) The location is verified as fire safe.
(b) Combustible materials are at least 35 ft from where hot work is being performed
(c) Fire extinguishers are in working condition readily available
(d) Ventilation is working properly
(e) Equipment is in working order
Substantiation: There are limited requirements on designated areas in NFPA 51B. The industry identified the need for some general requirements regarding designated areas. The task group developed requirements for users and AHJs to better understand the use of designated areas for hot work and emphasize that these areas need to be fire safe just as permitted areas.
CAL-OSHA and NFPA 51B
Lastly, for those of you working in the great state of California, NFPA 51B-2009 is NOW your Hotwork Compliance standard.
Article 88. Fire Prevention in Welding and Cutting Operations
§4848. Fire Prevention and Suppression Procedure.
(a) The employer shall establish a fire prevention and suppression procedure whenever any of the operations and processes covered by Sections 4794(a) and 4850(a) are conducted on its property. The employer shall issue and implement instructions on fire prevention and suppression procedures based upon the requirements contained in American National Standards Institute (ANSI/ASC) Z49.1-94, Safety In Welding, Cutting and Allied Processes, Chapters 3 and 6 and National Fire Protection Association (NFPA) 51B-2009, Standard for Fire Prevention During Welding, Cutting, and Other Hot Work, Chapters 3-7, which are hereby incorporated by reference.
(b) Welding blankets, curtains and pads shall be approved for their intended use in accordance with Section 3206 of these Orders.
FYI… CAL-OSHA’s PSM standard also refers to Section 4848.