NFPA 51B

Things you need to know about NFPA 51B

1. What Is the scope of the Standard?

NFPA 51B provides provisions to prevent loss of life and property from fire or explosion as a result of hot work.

2. What other organizations now look to NFPA 51B as the recognized standard for hot work practices?

NFPA 51B is now the hot works protocol referenced by the following agencies:

  • Occupational Safety and Health Administration (OSHA) 29 CFR 1910.252
  • Department of Energy (DOE) – 10 CFR 851
  • American Petroleum Institute (API) – API 2009

3. What are some of the requirements in the 2014 Edition?

“The 2014 edition includes a new definitions on designated and permitted areas. The scope has been modified to clarify that the document is also concerned with preventing injuries and not just loss of life during hot work operations. The purpose has been revised to clarify that this document provides requirements and not just guidance and that it applies to all those who are involved with hot work operations. A requirement has been added welding blankets, pads, and curtains to be both listed and approved.

– Page 1 of 2014 Standard

4. How does the Standard define Welding Blankets, Curtains and Pads?

Welding BlanketA heat-resistant fabric listed, approved, and designed to be placed in the vicinity of a hot work operation; intended for use in horizontal applications with light to moderate exposures such as that resulting from chipping, grinding, heat treating, sand blasting and light horizontal welding; designed to protect machinery and prevent ignition of combustibles such as wood that are located adjacent to the underside of the blanket.

Welding Curtain — A heat-resistant fabric listed, approved and designed to be placed in the vicinity of a hot work operation, intended for use in vertical applications with light to moderate exposures such as that resulting from chipping, grinding, heat treating, sand blasting, and light horizontal welding; designed to prevent sparks from escaping a confined area.

Welding Pad — A heat-resistant fabric listed, approved, and designed to be placed directly under a hot work operation such as welding or cutting, intended for use in horizontal applications with severe exposures such as that resulting from molten substances or heavy horizontal welding; designed to prevent the ignition of combustibles that are located adjacent to the underside of the pad.

5. What does the Standard say about Contractors’ Responsibility for Hot Work?

“Before starting any hot work, contractors and their clients shall discuss the planned project completely, including the type of hot work to be conducted and the hazards in the area.”

– Page 6 of 2014 Standard

6. What are some of the conditions that require “Listed or Approved” Materials before a Hot Work Permit is issued?

All combustibles shall be relocated at least 35 ft (11 m) in all directions from the work site, and the following criteria also shall be met:
If relocation is impractical, combustibles shall be protected by a listed or approved welding curtain, welding blanket, welding pad, or equivalent.

“To prevent the entrance of sparks, the edges of covers at the floor shall be tight, including at the point at which several covers overlap where a large pile is being protected.”

– Page 7 of 2014 Standard

“If hot work is done near walls, partitions, ceilings or roofs of combustible construction, they shall be protected by a listed or approved welding curtain, welding blanket, welding pad, or equivalent.”

– Page 7 of 2014 Standard

7. What is the requirement for Listed or Approved Materials on a Hot Work Permit?

The Standard includes a sample Hot Work Permit that includes “requirements within 35 ft (11m) of hot work.” One of the requirements is:

  • Other combustible storage material removed or covered with listed or approved materials (welding pads, blankets, or curtains; fire-resistive tarpaulins), metal shield, or noncombustible materials.

8. Why is using Certified Fabrics important?

In order for welding blankets, curtains, and pads to meet ANSI/FM 4950 they must undergo and pass stringent third-party testing, certification and ongoing audit procedures, and meet the conditions for safety, performance and quality. In addition, manufacturers must maintain a quality control program and submit to manufacturing facility inspections as part of the Approval process.

Annex A:  Explanatory Material

Annex A is not part of the requirements of this NFPA document but is included for informational purposes.

A.3.3.6 Welding and Allied Processes. The “Master Chart of Welding and Allied Processes” in ANSI Z491. Safety in Welding, Cutting, and Allied Processes, includes a list of welding and allied processes.

A.3.37 Welding Blanket. One such listing includes ANSI/FM 4950, American National Standard for Evaluating Welding Pads, Welding Blankets and Curtains for Hot Work Operations.

A.3.3.8 Welding Curtain. Once such listing includes ANSI/FM 4950. American National Standard for Evaluating Welding Pads, Welding Blankets and Curtains for Hot Work Operations.

A.3.3.9 Welding Pads. Once such listing includes ANSI/FM 4950. American National Standard for Evaluating Welding Pads, Welding Blankets and Curtains for Hot Work Operations.