For the type of metalworking process, see Hot working.
Hot work refers to operations which can produce a flame or spark.[1][2] Common hot work processes involve welding, soldering, cutting, brazing and the use of powder-actuated tools or similar fire producing operations. These processes produce sparks which can ignite flammable materials around the work area or flammable gases and vapors in the workspace. [3]
Welding temperatures vary depending on the type of electrode, but is typically higher than soldering.[5]
Desoldering of a 1210 capacitor using no flux.
Soldering
Soldering is the same type of joining process as welding but uses different filler material called solder and operates at under 450 degrees Celsius.[5] Soldering is commonly used in circuit boards and copper pipes in plumbing.
Aviation mechanic practicing brazing techniqes
Brazing
Brazing is used in applications to join close fitting members in the range of 0.001 to 0.005 inches.[6] Brazing operations are conducted at temperatures above 450 degrees Celsius.
Cutting
Cutting processes that produce sparks fall under the category of hot work. Examples include sparks produced from saw cutting and grinding. [7][8]
Safety
The hazards presented with hot work vary greatly, depending on the type of hot work used, the space and surroundings that the work is performed, and how to evaluate the best solution for the hazards present. While nearly every job involving hot work is unique in some way, there are some general steps that can be taken to help mitigate risk[9][10]:
Evaluate the workplace for potential hazards before performing the work
Consider moving the workplace to a safer location if possible or removing hazardous materials
In areas where there is particularly high danger, utilize a fire watch
Ensure everyone in the area is aware of the hazards present and where they are
After finishing work, keep a watch as the work piece cools to ensure nothing ignites
Personal Protective Equipment (PPE) is also an important part of safety in hot work. Many worksites cannot have the hazards eliminated or utilize components of the hierarchy of controls. Therefore, it is important for employers to emphasize the importance of PPE and for workers to utilize PPE in these conditions to mitigate risk wherever possible.[11]
Fire Watch
When performing hot work, welders must assess the risk of fire in the work area and implement certain safety precautions if a threat is detected. The establishment of a fire watch is the most important precaution a welder can take against an accidental fire on a job site. Either the welder himself or an appointed laborer must become designated for a fire watch and stay in the area of the hot work for no less than 2 hours after the last of the hot work has been completed. This designated fire watch person must have a fire extinguisher and access to phone in case of a fire.[12]
Hot Work Permit
In some countries, such as the UK and Canada,[13] a hot work permit is required for hot work.[14] The purpose of a hot work permit is to effect "the employer's written authorization to perform hot working operations".[15] The UK's Health and Safety Executive suggests that a hot work permit should specify:
what work will be done;
how and when it is to be done;
what safety and health precautions are needed;
who is responsible for checking it is safe for the work to start;
who will check that the work is done safely;
who is responsible for confirming that work is complete and there is no longer a risk from, or to, the people doing the work.[16]
Air quality testing for hazardous atmospheres inside a manhole
Confined Spaces
Confined spaces present a unique challenge with hot work for several reasons. Hot work performed in storage tanks, pipelines, and sewers present a risk of explosion due to the presence of flammable gasses.[17] Physical and chemical hazards in confined spaces are:
Limited access points make entering and exiting difficult
Poor ventilation and limited airflow can lead to the buildup of toxic and flammable gasses
Gasses such as Carbon Monoxide can buildup from hot work in confined spaces
Workers can face entrapment when physical barriers or equipment fails
In the united states, OSHA requires confined spaces where hot work is done to acquire a permit for hot work. [18] General requirements for hot work include[19]:
The employer shall post danger signs or other effective means of the existence, location, and danger posed by permit spaces
The employer must have a written permit confined space program available for inspection by employees
There are several specific circumstances in which an employer may qualify for exemptions from parts of the regulation, such as when the hazard present is solely a hazardous atmosphere and forced ventilation is utilized.
Standards
Most countries in the world use their own rules and regulations that have different responsibilities for both the employer and employee regarding safety and risk mitigation in the workplace, while some countries lack these rules or struggle to enforce them. The International Fire Code Chapter 35 presents a general framework for countries to adopt and utilize in the building of their own safety regulations regarding hot work.[20]
In the United States, OSHA maintains regulations for hot work in the marine industrial setting. The following regulations apply:
API RP 2009: Safe Welding, Cutting, and Hot Work Practices in the Petroleum and Petrochemical Industries, published by the American Petroleum Institute (API).[21]
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