What is the main strategy to prevent water pipes from freezing according to IS 6295?

The primary method is burying pipes below the local frost line, which is typically 1.8 to 2.4 meters deep, as per Clause 5.4.1 and Table 1.

When should heat tracing be used?

Heat tracing is recommended for pipes that cannot be buried below the frost line, are exposed to cold air, or are located in unheated spaces to provide active heating and prevent freezing (Clause 5.4.2.3).

How should drainage pipes be designed differently for cold regions?

Drainage pipes should be laid at steeper gradients to ensure rapid flow. Traps should be avoided in unheated areas or be protected with antifreeze or heating (Clause 6).

What kind of insulation is recommended?

The code recommends using insulation materials with low thermal conductivity, low moisture absorption, and non-flammable properties, with thickness as per Table 2 (Clause 5.4.2.2).

IS 6295

: 1986

Code of practice for water supply and drainage in high altitudes and sub-zero temperature regions

CurrentSpecializedCode of PracticeBIMMEP · Public Health Engineering

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This code of practice provides guidelines for the design, installation, and maintenance of water supply and drainage systems in high-altitude and sub-zero temperature regions. It outlines measures to prevent the freezing of water in pipes and drains, including deep burial, thermal insulation, and electrical heat tracing. The standard also covers appropriate material selection and modifications to standard plumbing fixtures for reliable operation in extreme cold.

Code of practice for water supply and drainage in high altitudes and sub-zero temperature regions

Quick Reference Values

Minimum burial depth for water mains1.8 m to 2.4 m below ground level

Minimum gradient for 100mm drains1:60

Typical insulation thickness for exposed pipes50 mm to 75 mm

Typical heat tracing power density15 to 25 W/m

Minimum temperature for design considerations-40°C

Practical Notes

Always confirm the local frost line depth from geotechnical surveys or local authorities, as it can be deeper than the general values provided in the code.

Pay close attention to insulating joints, valves, and supports, as these are common weak points where heat loss is greatest and freezing often starts.

For drainage systems, use steeper-than-normal gradients and avoid or protect P-traps to prevent water from stagnating and freezing, which can cause blockages and pipe bursts.