Difference Between Low Temperature Valves and Normal Temperature Valves in Marine Applications

In marine valve applications, low temperature valves and normal temperature valves are designed for different working conditions. Their main differences are as follows:

1. Operating Temperature Range

normal temperature valves are designed for media with temperatures ≥ -29°C (e.g. seawater, freshwater, fuel oil, compressed air).

Low temperature valves are designed for extremely low temperatures ≤ -29°C, such as -46°C, -101°C, -196°C, used for LNG, LPG, liquid nitrogen, etc.

2. Material Selection

normal temperature valves use conventional materials like carbon steel (WCB), stainless steel (CF8/CF8M), or bronze.

Low temperature valves require special low-temperature-toughness materials, such as:

Low-temperature carbon steel (LCB, LC2)

9% Nickel steel

Austenitic stainless steel (304, 316L)

Aluminum alloy, Monel alloy

These materials maintain ductility and toughness at  Low termperature temperatures, preventing brittle failure.

3. Structural Design

Normal temperature valves have standard designs without special considerations for thermal contraction.

Low temperature valves incorporate:

Extended bonnet (to keep packing away from the cold zone)

Special low-friction sealing materials suitable for low temperatures

Designs that minimize leakage and avoid jamming due to thermal contraction

4. Testing Requirements

Normal temperature valves are tested according to standard marine class rules (e.g. API, ISO, CCS, LR).

Low temperature valves undergo additional tests, such as:

Impact test at  Low temperature temperature

Low-temperature sealing and functional tests

5. Typical Applications

Item	Normal temperature Valves	Low temperature Valves
Medium	Seawater, freshwater, fuel oil, air	LNG, LPG, liquid nitrogen
Temperature	≥ -29°C	≤ -29°C
Typical Use	General ship piping systems	LNG carriers, LPG carriers,  Low temperature storage

 

Low temperature valves are specifically engineered for ultra-low temperature service, with materials, design, and testing tailored to prevent cold brittleness and leakage. normal temperature valves are not suitable for  Low temperature applications.