What is hot work?

So first off, what is hot work anyway?

OSHA defines hot work as work that includes “welding or cutting operations, use of spark-producing power tools, and chipping operations”.

Here’s my rule of thumb: Are you using a tool that could start a fire and burn the building down? Better evaluate for hot work. I would say you should take a closer look at hot work requirements any time you are using something that is capable of producing an ignition source (sparks) for flammable or combustible materials.

Welding is the typical activity that people think of when they hear the words “hot work”. But I would challenge you to include other activities as well. What about cutting metal pipes, grinding, or concrete cutting? You’ll need to decide which activities are considered hot work for your facility. As long as you are meeting or exceeding OSHA standards, you’ll be good to go.

Why is a hot work program important?

Why should we even bother with a hot work program in the first place (besides that pesky OSHA requirement)?

Well, the Chemical Safety Board (CSB) found that explosions and fires caused by hot work are among the most common incidents it investigates. Yikes.

According to the Bureau of Labor Statistics, fires and explosions are in the top six most-common causes of fatal workplace accidents and accounted for 115 fatalities in 2019. It would be reasonable to assume many of these fires and explosions were caused by hot work.

That’s a lot of injuries and fatalities caused by hot work. Not to mention all of the property damage, lost production time, reputation damage, and everything else that goes along with a large incident. Guess hot work is pretty important, so we should make sure to prevent hazards caused by hot work at all costs.

Where does OSHA talk about hot work?

So, for those of you “reg nerds” that care to know, you can find the OSHA regulations governing hot work (for general industry) in 29 CFR 1910, Subpart Q, or 1910.251-255.

The Basics

Just a note before we begin: Performing hot work inside of a confined space is especially hazardous. Please be really careful.

Alright, let’s talk about some general best practices for hot work. Many of these are also regulatory requirements, so make sure to consult your handy OSHA reg book (or go to the eCFR).

Best Practices for Hot Work

Ensure the area is free of any combustible materials such as wooden pallets, cardboard, wood shavings, etc. Use a fire blanket or other guard to cover anything that cannot be moved.
Always have a fire watch with a fire extinguisher at the ready. Make sure the fire extinguisher is the appropriate type for the work being done and make sure the fire watch is trained in its use.
If you will be working on walls, the floor, or any other surface on which the other side could be impacted, make sure you think about the implications of the other side. You may need a fire watch for each side.
Make sure other workers in the area know about the hot work about to take place. Inform them of any hazards that may affect them.
You cannot perform hot work:
- In areas not authorized by management.
- When the fire sprinkler system is impaired or out of service (for buildings that have fire sprinkler systems).
- In the presence of explosive atmospheres (mixtures of flammable gases, vapors, liquids, or dusts with air).
- In areas where explosive atmospheres may develop, such as inside uncleaned or improperly prepared tanks or equipment which have previously contained flammable materials, for example.
- In areas with an accumulation of combustible dusts (sugar explosions, anyone?).
- In areas near the storage of large quantities of exposed, readily ignitable materials such as bulk sulfur, baled paper, or cotton.
Make sure to keep in mind any hazard communication requirements. All hazardous materials used during hot work, such as fluxes, coating, coverings, etc should be properly labeled. Also keep in mind any hazardous materials that could be released into the air during the hot work activity, such as during welding.
All workers should have access to the safety data sheets for such materials, and should be trained on the hazards before working with the materials.

Responsibility

Each person involved in hot work has their own responsibility

A key to any successful program is making sure the facility leadership backs you up and supports the program. Otherwise, you are headed for a rough road to failure my friend. You need to make sure the managers and supervisors are on board and give their endorsement. For more on this topic, consider taking my course on safety culture.

Management is responsible for designating who can issue and authorize permits and for ensuring everyone is properly trained. Management is also responsible for ensuring all contractors are made aware of flammable materials or hazardous conditions when they are performing hot work on your worksite.

You may find it helpful to assign someone to be the Hot Work Program Administrator. This person (it might be you, and that's fine too) will be responsible for:

Keeping copies of the permits on file after they are completed.
Updating procedures as necessary.
Ensuring all appropriate employees, contractors, permit writers, and fire watches are properly trained and that they conduct hot work safely.

Supervisors are specifically called out in the OSHA regulations as having responsibilities relating to hot work activities. Supervisors must:

Make sure hot work equipment is handled and used safely.
Determine where combustible materials or hazardous areas are located.
Ensure all combustible materials are protected before beginning work (more on this in “Preparing the Area for Hot Work”).
Get the proper authorization for hot work from the designated permit writer.
Make sure the fire watches are available and have all of the required fire extinguishing equipment.
Determine that the conditions are safe before work begins.

There is also accountability on the employees who will be involved with hot work. It's their responsibility to make sure they are aware of the program's requirements and ask questions if they don't understand. Everyone has an obligation to stand up and say something if something doesn't feel right or seems at all unsafe.

The Hot Work Permit: Who, What, When, Where, and How

The hot work permit serves as your guide for ensuring the work will proceed safely.

Make sure to have the following on your permit:

Who is doing the hot work
What equipment is being worked on
What tools are being used
When the work will start and end
Where the work will be done
What the atmospheric conditions are, including oxygen and the lower explosive limit (more on this later)
How the activity is to be made safe – ensuring the area is made safe, personal protective equipment (PPE) requirements, lock out tag out, etc.

The hot work permit will be issued by the Hot Work Permit Issuer. We will discuss more about the different roles below.

Make sure you get all required signatures before you start work. All involved employees and contractors should be thoroughly briefed on the potential hazards in the area, locations of emergency equipment such as fire extinguishers, how to use applicable emergency equipment, how to respond in an emergency, and how to summon for assistance.

You may want to consider writing your permit in such a way that if conditions change, such as an increase in flammable vapors, the permit must be reauthorized before work can continue. This will help ensure work doesn’t continue when unsafe conditions haven’t been addressed.

A copy of the hot work permit should remain near where the work is happening for the duration of the work. This will allow others to review the permit if needed, so they can understand the work happening and how the hazards have been controlled. Once the work is complete and all necessary signatures have been received, the permit should be kept on file for future reference if needed.

Coach’s Tip: Before you file the permit, make sure the permit is filled out completely – missing information on a permit is low-hanging fruit during an audit.

Hot Work Permit Issuer: With Great Power Comes Great Responsibility

You must authorize specially trained workers to be permit issuers.

Do you really want just anyone issuing a hot work permit that could potentially prevent your building from burning down? I didn't think so. You'll want to train someone (or multiple someones) to properly fill out a permit.

This person, known imaginatively as the "Permit Issuer", should:

Be effectively trained to recognize hazards related to hot work
Know how to prepare the area
Ensure the work can safely happen

The permit issuer needs to be someone designated by the company to issue hot work permits. This person is responsible for knowing and following the policy. Most importantly, this person is responsible that everyone goes home safe. The permit issuer must understand the risks and hazards associated with the hot work project. It’s a lot of responsibility for one person, but permit issuers are a key piece of an incredibly important process that allows potentially dangerous work to proceed without issue or incident.

Preparing the Area for Hot Work: More than just housekeeping

It’s super important to make sure you prepare the area for hot work before beginning.

If possible, choose a location for your hot work that is already free of dangerous combustibles. A wide-open parking lot makes a great place for small welding jobs or cutting metal pipes.

If moving the hot work activity to a safe location isn’t possible, you must make sure the area is safe before proceeding. This includes:

Making sure the floor is swept clean for a radius of 35 feet to remove any combustible materials.
If the floor itself is combustible, make sure the floors have been wet down, covered, or otherwise protected by fire-resistant shields.
Removing all combustible materials within a 35 foot radius, when possible. Cover all remaining materials with fire blankets or other fire-resistant shields.
Shutting down or protecting any ducts or conveyor systems that might carry sparks to other areas.
Properly isolating and locking/tagging out the equipment to be worked on (if applicable).
Ensuring all drums, tanks, or containers are free of flammable materials and have been thoroughly cleaned. Even a small residue left behind can lead to a very bad outcome if not removed properly. For a great visual on why this is so important, see this video. Always ensure the container has been vented and purged of all flammable gases. Let it air out sufficiently or purge with inert gas.

Atmospheric Conditions: Not Just for Meteorologists

Making sure the atmospheric conditions are acceptable before and during hot work can save lives.

An important piece of making sure the area is safe before hot work begins is the atmosphere. You may be working outside where there is a fresh breeze and birds chirping, and if so, you are probably ok. However, regardless of where you are doing hot work, you need to check the atmosphere. There are a ton of ways that the "air can go bad" and create a very dangerous situation. What if there is not enough (or too much) oxygen? Both are bad. What if there is another flammable gas in the air, just waiting for a little spark to make the whole place go kaboom?

You can see how taking just a few minutes to do an air check before you begin could avoid a potentially horrible situation. Four gas meters, such as this one, are relatively easy to use and very reliable.

Most four gas meters will evaluate the air for four things:

Percentage of oxygen - should be between 19.5 and 22 percent (recommended)
LEL - lower explosive limit - used to measure the amount of flammable gas in the air. For hot work activities, it’s recommended that the LEL should be below 1%, ideally 0%.
CO - carbon monoxide - an asphyxiating gas that may be generated from incomplete combustion
H2S - hydrogen sulfide - a deadly gas that smells like rotten eggs

If the air readings are outside of the acceptable ranges, you may need to provide mechanical ventilation. Sometimes a blower, such as this one, is all you need to provide a fresh air flow.

Coach’s Tip: Ensure atmospheric conditions are checked both before and during (every 15 minutes or so) hot work. Some companies require continuous monitoring, to ensure any changes in conditions are identified immediately.

Fire Watch: You have one job (but really, only one)

A fire watch must be present at all times during hot work activity to identify and extinguish any possible fires.

The fire watch must monitor the hot work activity. This person cannot be engaged in any other activity. The fire watch must be aware of the hazards in the area, location of emergency equipment, trained in the use of a fire extinguisher, and how to summon assistance. The fire watch is required to stop any unsafe operation or activity. Specific duties include:

Watch for fires, smoldering material, or other signs of combustion.
Be aware of inherent hazards of the work site and of the hot work.
Ensure that safe conditions are maintained during hot work operations and stop the hot work operation if unsafe conditions develop.
Have fire-extinguishing equipment readily available and be trained in its use.
Extinguish fires, but only when the fires are obviously within the capacity of the equipment available. If the fire is too large or aggressive, the fire watch should sound the alarm immediately and evacuate.
Be familiar with the facilities and procedures for sounding an alarm in the event of a fire.
More than one fire watch shall be required if combustible materials that could be ignited by the hot work operation cannot be directly observed by a single fire watch (e.g. in adjacent rooms where hot work is done on a common wall).

The fire watch must be maintained for a minimum of 30 minutes after completion of the hot work to prevent, detect, and extinguish possible smoldering or ensuing fires.

When hot work is done in an area that is normally unoccupied or that will be unoccupied for a period of time immediately following the hot work, an extended fire watch coverage should be considered. An example of extended coverage would require the fire watch to stay in the area for 60 minutes following the completion of the hot work and monitoring (walk through) of the area every 30 minutes for an additional 3 hours. Examples of areas which should be considered for extended coverage include, but are not limited to:

Warehouses after normal working hours.
Office and lab areas after normal working hours.
Building roofs.
Areas occupied at the time of the hot work but that will be vacated prior to four hours after completion of the hot work.

Hazardous Areas: Where things can go boom

Certain areas may present hazards that complicate hot work activities.

You may have heard of locations referred to as “Class 1 Division 1” or “Class 1 Division 2”. These are referring to different types of hazardous areas. What makes them hazardous? It’s not that an annoying co-worker works in that area (that’s a different type of hazard not covered in this article). It’s because there are flammable gases or vapors present (or possibly present) that may lead to fire or explosion if given an ignition source.

A hazardous area is an area that is defined as hazardous by the NFPA and fits either the definition of being a Class 1 Division 1 location or a Class 1 Division 2 location. An area not meeting the definition of a Class 1 Division 1 location or a Class 1 Division 2 location is classified as a non-hazardous area.

You need to evaluate your worksite for these locations to see if you need to make special arrangements before proceeding with hot work in these areas. Here are the definitions:

Class 1 Division 1 Location: A location in the facility where:

Ignitable concentration of flammable gases or vapors exist under normal operating conditions; or
Ignitable concentrations of such gases or vapors may exist frequently because of repair or maintenance operations or because of leakage; or
Breakdown or faulty operation of equipment or processes might release ignitable concentrations of flammable gasses of vapors and might also cause simultaneous failure of electrical equipment

Class 1 Division 2 Location: A location in the facility:

In which volatile flammable liquids or flammable gases are handled, processed, or used, but in which the liquids, vapors, or gases will normally be confined within closed containers or closed systems from which they can escape only in case of accidental rupture or breakdown of such containers or systems, or in case of abnormal operation of equipment; or
In which ignitable concentrations of gases or vapors are normally prevented by positive mechanical ventilation, and which might become hazardous through failure of abnormal operation of the ventilating equipment; or
That is adjacent to a Class 1, Division 1 location, and to which ignitable concentrations of gases or vapors might occasionally be communicated unless such communication is prevented by adequate positive-pressure ventilation from a source of clean air and effective safeguards against ventilation failure are provided.

You should consider requiring extra safeguards when conducting hot work in hazardous areas, such as continuous air monitoring in the hazardous area (including inside connecting vessels/equipment).

Training

Everyone should be effectively trained before participating in hot work activities.

Everyone involved with hot work, including the permit writers, fire watches, employees performing the hot work, and employees in the surrounding area – should be effectively trained. I say "effectively" because just because you shove everyone in a room for a given period of time and show them some PowerPoint slides does not mean those people were "effectively" trained.

Here’s a helpful video you can use during training, showing the dangers of hot work and the importance of taking safety measures.

Tips & Takeaways

The fire watch has one job - to watch for, and if necessary, extinguish any fire or smoldering materials. That job does not include games on his/her phone, assisting the other workers, chatting with coworkers, or running to go get something, even if it's just "real quick".
Equipment and areas must be rendered safe, cleared, and free of flammable and/or combustible materials and other hazardous materials, including combustible dusts. Items that cannot be removed must be shielded, i.e., covered with fire blankets to prevent hazardous conditions.
Ensure associated hot work tools and equipment being used are in good, serviceable condition and safe to use.
Areas that are enclosed or highly congested must be properly ventilated to prevent atmospheric conditions from changing as work is performed.
Other work activities in the area must be evaluated for potential hazards and implications to the pending hot work activities. Concrete core drilling from one floor/level to another, for example, should consider a fire watch on both floors.

A Beginner's Guide to Hot Work

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