What is the main classification for silicone sealants under this code?

They are classified by their Movement Accommodation Factor (MAF). Class 25 for ±25% movement and Class 20 for ±20% movement are typical (Table 2).

What is the acceptable hardness range for these sealants?

The Shore A hardness should be between 15 and 50, as per Table 1.

What is the maximum time a sealant can take to become tack-free?

The maximum tack-free time is 180 minutes (Table 1).

Does this standard specify the color of the sealant?

No, the color is subject to agreement between the purchaser and the supplier (Clause 5.1).

What is the criteria for passing the adhesion and cohesion test?

The sealant should not show any adhesive or cohesive failure after 10 cycles of extension and compression (Annex B).

IS 15588

: 2005

Silicone based sealants for construction - Specification

CurrentSpecializedSpecificationBIMMaterials Science · Waterproofing and Damp Proofing

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This standard specifies the requirements and test methods for single-component, gun-grade, silicone-based sealants used in construction joints. It classifies sealants based on their movement accommodation factor and details performance criteria for adhesion, cohesion, durability, hardness, and curing characteristics.

Specifies requirements for one-part and two-part silicone based sealants for use in building and civil engineering constructions.

Quick Reference Values

Movement Accommodation Factor (Class 25)±25%

Movement Accommodation Factor (Class 20)±20%

Hardness Range (Shore A)15 to 50

Maximum Tack-Free Time180 min

Maximum Curing Time14 days

Maximum Loss in Mass on Heat Ageing10%

Elastic Recovery (minimum)80%

Practical Notes

Proper joint design (width-to-depth ratio) and thorough surface preparation are critical for sealant performance and longevity, often more so than the sealant properties alone.

Always check for compatibility between the sealant, substrate, and any primers used, as specified by the manufacturer, to prevent adhesion failure.

Do not confuse silicone sealants with other types like polysulphide or polyurethane; they have different properties, chemical resistance, and application areas.