2. INSULATION MATERIALS AND PROPERTIES

2.7 ACCESSORIES

Print 

The term "accessories" is applied to devices or materials serving one or more of the following functions:

1. Securement of insulation and/or jacketing

2. Reinforcement for cement or mastic applications

3. Stiffening around structures which may not support the weight of high density insulations

4. Support (pipe, vessel and insulation)

5. Sealing and caulking

6. Water flashing

7. Compensation for expansion/contraction of piping and vessels

Improper design or application in one or more of these accessories is a significant factor in the failure of insulation systems.

Securements: As most insulations are not structural materials they must be supported, secured, fastened or bonded in place. Securements must be compatible with insulation and jacketing materials. Possible choices include:

a. Studs and pins

b. Staples, serrated fasteners, rivets and screws

c. Clips

d. Wire or straps

e. Self-adhering laps

f. Tape*

g. Adhesives*

h. Mastics*

*Ambient temperature, humidity conditions and substrate surface cleanliness affects the efficiency of tapes and adhesives and mastics on certain installations. Check the properties of temperature range and vapour permeability before choosing adhesives. And, wherever possible, use mechanical securements.

Reinforcement for cements and mastics: Mastics and cements should be reinforced to provide mechanical strength. The following materials can be used:

a. Fiber fabrics

b. Expanded metal lath

c. Metal meshes

d. Wire netting

Compatibility of materials must be considered to prevent corrosion.

Flashing: Materials which direct the flow of liquids away from the insulation may be constructed of metal, plastic or mastic.

Stiffening: Metal lath and wire netting can be applied on high temperature surfaces before heavy density insulation is applied.

Supports: Pipe supports and accessories may be supplied in part or totally by the insulation contractor. Insulation treatment at points of support are illustrated on Details. Accessories at points of support are:

a. Heavy density insulation inserts

b. Pipe support saddles and shoes

c. Insulation and metal shields used to protect insulation

d. Wood blocks or dowels; these should not be used at below ambient temperatures

Insulation support rings on vertical piping and vessels should be supplied by the piping or vessel contractor, as field welding on coded piping or vessels voids the original coding by the manufacturers. See Detail for treatment.

Sealing and caulking: A variety of sealers, caulking and tapes are available for sealing vapour and weather-barrier jackets, joints and protrusions. These products are manufactured in a large range of temperature and vapour permeability properties. Some are designed specifically for use with one type of insulation or manufacturer's products.

Expansion/Contraction compensation: Accessories used in the design of expansion/contraction joints, etc. include:

a. Manufacturer overlapping or slip joints

b. Bedding compounds and flexible sealers

See Details for insulation treatments.