In addition to saving energy, pipe and vessel insulation has two critical roles in refineries and chemical processing plants: controlling process temperature and protecting workers. Insulation failure can result in injury, fire danger, material waste, and equipment damage. If your plant was shut down or damaged by flooding, natural disaster, or fire you need to be sure the insulation is still functional before restarting. Here is what to look for and what to do about it:

Wet Insulation

• Thoroughly wet calcium silicate or perlite insulation may be left in place on piping that will operate at 400ºF or greater if the jacket is still structurally secure and the insulation is not deformed or sagging. Heat up the system gradually to allow vapor to escape slowly and minimize the risk of damage to the insulation and pipe.


• Saturated fibrous insulation will sag, leaving the top of a horizontal pipe underinsulated. If the insulated pipe appears to be out of round with a teardrop or pear shape, the waterlogged insulation is sagging and must be replaced (as illustrated above -- sagging insulation leaves top of pipe underinsulated). Insulation on vertical runs that show evidence of jacket "ballooning" or rupture should also be replaced.


• Fibrous insulation that is only damp and is not deformed or structurally damaged will likely dry out in normal service on piping of 250ºF or greater operating temperatures. Gradual heat-up is recommended.

Corrosion Under Insulation

• Calcium silicate or perlite insulations are manufactured with anticorrosive silicates that help prevent corrosion, even if the insulation gets wet.


• Fibrous and cellular glass insulations should be the first priority in corrosion inspections, particularly if they have been exposed to salt water or other high-chloride chemicals.

Short-Term Repair Options

• Where damage to the insulation has exposed the pipe, consider installing FSK-faced mineral fiber or fiberglass flexible insulation as a temporary fix. This will reduce energy consumption and protect personnel from injury. This type of insulation can be quickly installed, and when properly sealed will serve until a permanent insulation installation can be scheduled.


• Cracks or breaks in calcium silicate or perlite insulation can be repaired using high-temperature accessory adhesives or cements. IIG distributors carry a complete line.

Mechanical Considerations

• Bands that hold the insulation jacketing in place should not be loose or sagging. A broken band is an indication that the insulation is waterlogged.


• Replace jacketing that is loose or torn.


• Ruptured jacket is a sign of severe mechanical damage or saturated insulation, and should be replaced or repaired only after addressing the root problem.


• Inspect the pipe hangers to ensure that the saddles supporting the insulated pipe are in place.


• Consider the traffic pattern of the restoration and maintenance workers: piping runs where heavy foot traffic can be anticipated should be insulated or reinsulated with calcium silicate. This rigid insulation stands up to mechanical abuse and delivers long-term insulation performance. (As shown above, pipes passing through areas with human activity are likely to be used as walkways, hangers, ladder supports, even climbing walls. Calcium silicate, installed as a retrofit on the pipe at left, is the best choice in these conditions; fibrous insulation on the right does not have the compressive strength to stand up to this type of abuse.)