Choosing Insulation | Bishop Engineering

Quick pick (TL;DR)

Hot service → mineral wool (to ~650°C) or calcium silicate (rigid, abuse-resistant).
Cold service → cellular glass or PIR/PUR with a vapour barrier.
Personnel protection → enough thickness to keep the surface ≤ 60°C.
Cladding: aluminium (indoor), stainless (corrosive/wash-down).
Always vapour-seal cold lines.

Step 1 — Define the purpose

Purpose	Drives
Heat conservation	Economic thickness.
Personnel protection	Surface ≤ 60°C.
Anti-condensation	Surface > dew point + barrier.
Acoustic / fire	Special / rated systems.

Step 2 — Material by temperature

Material	Range	Notes
Mineral / rock wool	up to ~650°C	General hot service.
Calcium silicate	up to ~650°C	Rigid, abuse-resistant.
Cellular glass	−200 to 430°C	Cold / cryogenic.
PIR / PUR foam	−180 to 120°C	Cold service.
Aerogel	up to ~650°C	Thin, high-performance.

Step 3 — Surface-temperature check

Personnel protection (concept)

Goal touchable surface temperature ≤ 60°C Heat balance heat through insulation = heat lost from surface k·(T_pipe − T_surf)/x = h·(T_surf − T_amb) Use increase thickness x until T_surf ≤ 60°C e.g. 250°C steam, DN150 → ~80 mm mineral wool (confirm with a tool e.g. 3E-Plus / NAIMA)

Iterate thickness to meet the surface target; finalize with 3E-Plus.

Step 4 — Cladding & vapour barrier

Cladding: Al indoor; SS corrosive; GRP buried.
Cold lines need a continuous vapour barrier.
Beware CUI on 50–175°C CS — coat & seal.

Common mistakes

No vapour barrier on cold lines.
Exceeding material temperature limit.
Ignoring CUI.

Requisition & datasheet

Purpose, material, thickness, cladding.
Vapour barrier, surface target, fixing.

Frequently asked questions

What should I know about Choosing Pipe Insulation?

Hot service → mineral wool (to ~650°C) or calcium silicate (rigid, abuse-resistant). Cold service → cellular glass or PIR/PUR with a vapour barrier. Personnel protection → enough thickness to keep the surface ≤ 60°C. Cladding: aluminium (indoor), stainless (corrosive/wash-down). Always vapour-seal cold lines.

Which standards or codes apply?

ASTM C547/C533/C552 (materials); CINI / project insulation spec; economic & surface-temperature thickness by 3E-Plus (ASTM C680 method).

Standards — ASTM C547/C533/C552; CINI; ASTM C680 (3E-Plus).

Choosing Pipe Insulation