Fire Prevention and Hot Work Permits at Biodiesel Plants

Industrial fires and explosions represent only six percent of all fires but can have lasting effects on employees and businesses. The key to fire prevention is to follow the plant's hot work permit system and proper coordination.
By David Ayers | June 15, 2010
In spring 2008, a group of subcontractors was welding on pipes at an idled biodiesel plant in the eastern U.S. when an explosion occurred, killing one of them. Industrial fires have an untold impact on the economy and human life, and can cause some companies to go out of business. Even if no one is injured, workers can be displaced from their jobs as the facility is rebuilt.

Approximately six percent of fires in industrial properties and many fires in other properties have been caused by cutting and welding, primarily with portable equipment in areas not specifically designed or approved for such work. Cutting and certain arc welding operations produce literally thousands of ignition sources in the form of sparks and hot slag. Electric arc or oxygen-fuel gas flames and hot works are also inherently ignition sources. The majority of fires, in which cutting and welding are factors, have been caused by these sparks (NFPA 51B, section A.1.1.1). These sparks, or globules, can travel as far as 35 feet setting fire to a variety of combustible and flammable materials. Sparks can also fall through cracks or other small floor openings and set fire to the area beneath the hot work. Likewise, these sparks can also travel via a belt to be deposited in another area of the facility. These areas are not likely to be monitored as the hot work is taking place somewhere else. Hot work is defined as work involving burning, welding, or a similar operation capable of initiating fires or explosions. Hot work operations are vital in keeping our facilities operating smoothly but, if done incorrectly, can have dire consequences.

This article will help determine if a hot work permit is needed, and how to prepare areas for hot work and put a system in place to ensure permits are obtained before starting. Other permits may also be needed to complete hot work, such as confined space entry, line break permit or a ventilation/exhaust permit. Additionally, lockout/tagout may be required to safely complete the hot work. Finally, contractors will be discussed since some facilities don't possess in-house equipment and expertise to perform hot work. The premise of the article is to follow the OSHA regulations for Welding, Cutting and Brazing found at 29 CFR 1910.252, General Requirements and the National Fire Protection Association's (NFPA) 51B: Standard for Fire Prevention During Welding, Cutting and Other Hot Work; 2009 Edition. Hot work operator and fire watch personal protective equipment will not be covered under the scope of this article.

The responsibility for the hot work to be completed safely rests with facility management. The first step in safely completing hot work is to determine if a hot work permit is needed. The key to plant fire prevention is to never have one. Limit sources of combustion and control sources of ignition. A hot work permit is needed if the hot work will occur in an area where combustible materials such as paper, wood shavings, and combustible or flammable liquids are present. The company or site can designate a permanent area approved for hot work where no permit is needed, such as a detached location or the plant's maintenance shop, which is of noncombustible or fire-resistive construction, essentially free of combustible and flammable contents and segregated from adjacent areas.

In deciding if a hot work permit is necessary, first try to look for alternatives to having an open flame or creating any flying sparks. Some alternatives to hot work include mechanical bolting, screwed, flanged or clamped pipe, reciprocating saw or mechanical pipe cutter.

If hot work is still necessary after examining alternatives and moving the work items to the hot work designated area, a hot work permit must be issued by the facility management for authorization. The person at the facility that issues the hot work permits is the permit authorizing individual (PAI) and may be the supervisor, foreman or a member of safety and health team. The PAI should never be the hot work operator unless they are a sole-proprietor, in which case the operator can authorize to serve as the PAI and as fire watch if a written checklist is followed to serve as a hot work permit. The PAI should always inspect the jobsite for the site-specific conditions to ensure the hot work can be performed safely. Additional permits may also have to be obtained, such as a line break permit to ensure the line has been purged of any liquids before work begins. Also, cleaning the pipes will greatly reduce fire potential. Any remaining liquid or vapor in the pipes may catch fire when extreme heat and sparks are introduced. If the plant cannot ensure the pipes have been purged and are fire-safe prior to starting hot work, use a method to break the line that won't create sparks.

A hot work permit should only be authorized after all combustible materials have been removed at least 35 feet. Potentially some items may not be removed due to size and weight. The hot work operator can protect these combustible items by using welding blankets, curtains and pads that are listed and approved. Many of these items are listed by ANSI/FM 4950 American National Standard for Evaluating Welding Pads, Welding Blankets and Welding Curtains for Hot Work Operations. Check the item's tag for details.

Even with these additional safeguards, a dedicated fire watch will be needed. Part of the fire watch's job is to look for fires in the incipient stage and prepare to extinguish it quickly or call for help. The fire watch also looks where slag and sparks are flying, since the hot work operator is focusing on the task at hand. The fire watch should have a fully charged fire extinguisher and be trained in all the site's emergency procedures. They should also have the authority to stop the project if unsafe conditions develop. The fire watch is also a dedicated responsibility that extends for at least 30 minutes after hot work completion. Some site-specific areas may require more than one fire watch due to plant configuration. The fire watch must be able to monitor where all the slag or sparks are going. Such situations could be on an elevated platform with slag or sparks falling to a lower floor.

One of the PAI issuer's jobs is also to ensure a false plant evacuation doesn't occur. Depending on where the hot work is taking place, air handlers, smoke detectors and other fire detection equipment may need to be isolated to ensure the fire detection system doesn't go off due to the work being performed. If previous plant evacuations have resulted in a "boy who cried wolf" scenario, regardless of the emergency alarm, employees will soon always try to determine if the evacuation is warranted before evacuating-a dangerous mindset that can creep into the workplace if false evacuations occur. If the hot work is close to fire sprinkler heads, then they must be protected from contact (either incidental or from the heat created from hot work). Physical barriers and even wet rags can help.

A hot work permit system can be a standalone system or integrated into a larger system of work permits including confined spaces and lockout/tagout of machinery and process equipment. There are also paperless systems in place where the open and cancelled hot work permits are archived and help assist the company in future fine-tuning of the hot work program. Whatever hot work permit system the plant uses, it must be user-friendly. This way, employees better understand it and potential liabilities for not following the system. A user-friendly system will also help with program acceptance if it is still in the development phase and must still be rolled out to employees. As with anything new, there will be some learning required and a little uncertainty upon initial roll out.

If the hot work permit system is part of a larger permit system, this will help employees identify all the potential areas and items that may need to be locked out as well as the requirements for confined space entry or the purging and breaking of any process lines. Accidents and incidents not associated with hot work can also occur if items are not placed out of service correctly to have maintenance performed on them.

There is a general trend toward outsourcing any specialized maintenance work, especially for plants that don't have personnel with the necessary skills, or all the required personal protective equipment and an area for proper bottled gas storage. Any contractors being brought onto the property should be vetted for their ability to complete the job safely and adequate insurance coverage, and their safety procedures and plans should be reviewed. Part of the contractor selection process should be a project meeting to discuss the job's scope, along with covering specific work procedures and permits to be used. The plant should ensure its hot work permit system is used unless the contractor can prove a greater degree of safety by using his own hot work program. The lowest bid or price does not always ensure a smooth, accident- or fire-free project. Proper planning and coordination are the keys.


-NFPA 51B Standard for Fire Prevention During Welding, Cutting and Other Hot Work; 2009 Edition-reprinted with permission from NFPA 51B, Fire Prevention during Welding, Cutting, and other Hot Work 2008, National Fire Protection Association. This reprinted material is not the complete and official position of the NFPA on the referenced subject, which is represented only by the standard in its entirety.

-OSHA 29 CFR1910.252, Welding, Cutting and Brazing

David Ayers is the principal consultant at Applied Safety Management. Reach him at (443) 896-7540 or [email protected].
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