What is the recommended overlap for metal cladding?

A minimum of 50 mm for both circumferential and longitudinal joints to ensure weather tightness (Clause 6.2.2).

How should insulation be applied in multiple layers?

The joints of each successive layer must be staggered with respect to the joints of the underlying layer (Clause 5.3).

How is insulation secured on vertical piping?

In addition to circumferential wiring/bands, insulation on vertical runs should be supported by angle iron rings welded to the pipe at specified intervals (Clause 5.2.2).

Are special provisions needed for flanges and valves?

Yes, they should be insulated using removable and reusable boxes or covers to allow for maintenance and inspection without damaging the main insulation (Clause 7).

IS 7268

: 1993

Recommended practice for hot application of thermal insulation

CurrentSpecializedCode of PracticeBIMMEP · Insulation Materials

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This standard provides recommendations for the methods of applying thermal insulation to hot surfaces operating at temperatures above ambient. It covers material selection, surface preparation, application techniques for various insulation forms, and protective finishing to prevent damage and moisture ingress.

Provides recommended practices for the hot application of thermal insulation materials.

Quick Reference Values

Minimum overlap for longitudinal and circumferential jacketing50 mm

Maximum spacing of securing wires on pipes up to 300mm dia250 mm

Minimum thickness of aluminum jacketing for general use0.71 mm

Minimum thickness of galvanized steel jacketing for general use0.50 mm

Minimum end lap for blanket or mattress insulation25 mm

Practical Notes

Thorough surface preparation is critical to prevent Corrosion Under Insulation (CUI), a major cause of asset failure.

Ensure all joints in the outer metal jacketing are correctly overlapped and sealed to prevent water ingress, especially for outdoor installations.

For multi-layer applications, ensure all seams are staggered to prevent direct heat paths and improve efficiency.