Insulation |


Insulation is required for worker safety and for energy efficiency. Some types of insulation can also act as a corrosion inhibitor. Old insulation that contains asbestos has become an environmental issue. All of this adds-up to make a simple topic like insulation become very complex.

All hot surfaces should be insulated. This includes:

  • steam lines and hot water pipes

  • condensate return lines and collection vessels

  • boilers

  • deaerators

  • blowdown vessels used for heat recovery

  • all valves, fittings and controls where practical

It is rare to find uninsulated pipes, but it is common to find poorly insulated pipes and vessels. Insulation must be in good condition to be effective. Wet insulation is worse than no insulation.



OSHA considers exposed heated surfaces, if there is a potential for injury, to be a hazard and will issue citations if employees can come into contact with such surfaces. While there are not any OSHA standards, except those that are applicable only to specific industries, which address exposed heated surfaces, there are several OSHA general standards which address such hazards. Such as:


“Steam and hot-water pipes. All exposed steam and hot-water pipes within 7 feet of the floor or working platform or within 15 inches measured horizontally from stairways, ramps, or fixed ladders shall be covered with an insulating material, or guarded in such manner as to prevent contact.”

Source: OSHA web site 4/2005 at

Note: Generally accepted surface temperature is to be less than 140F; Canada is 70C.

Type of Insulation

Insulation used for boilers and pipes will be of these general types:

  • high density fiberglass shaped for pipes or flat sections
  • blankets or batts of fiberglass or mineral wool
  • molded, fire brick, pre-cast or cast-in-place
  • spray-on ceramic
  • spray-on foam (more common in cold applications than hot)

The insulation is generally covered with some sort of metal, plastic, paper, etc., to protect it from light impact damage, UV exposure and moisture.

More Information

Ceramic Insulation

Insulate Fittings

Insulate Steam Pipes

Air Infiltration


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