Low Temperature O-Rings

Low Temperature O-ring Materials:

Many compounds support a sub degree service temperature. These materials are the most often used in extreme low temperature applications extending to under -65°F. Elastomers can be compounded with different properties for different low temperature gradients. Temperature ranges are recommendations with a margin of safety when setting the general operating temperature of common elastomers.

O-rings have an advantage of holding a strong seal through a wide range of temperatures. Considering the minimum temperature will help narrow down material choices. Range of withstood temperature is important for applications that will swing from hot to cold and vice versa, in addition to the products that will be used to seal multiple types of projects.

How Is Low Temperature Resistance Measured?

Low temperature resistance is measured by determining the flexibility of an elastomer at a given low temperature.

  1. The lowest temperature at which the seal is expected to function should be determined.
  2. The low temperature test method that most nearly simulates the actual service requirement should be chosen to give the best possible assurance that the seal which passes this test will function in the application. Parker believes that the Temperature Retraction Test (TR-10) is the best method for determining a compound’s ability to seal at low temperatures. Most low temperature tests are designed to indicate the brittle point of a material. This only tells at what low temperature the compound is most likely to be completely useless as a seal in a standard design, but very little about the temperature at which it is useful. This is not the case with TR-10 that consists of stretching 3 or 4 samples 50%, freezing them, then warming them gradually at a constant rate, and finally recording the temperature at which the samples have returned to 9/10 of the original stretch (1/10 return). This temperature (TR-10) then is the lowest temperature at which the compound exhibits rubber-like properties and therefore relates to low temperature sealing capabilities. Functional tests indicate that O-rings will usually provide reliable dynamic sealing at or below the TR-10 value. Static O-rings normally function satisfactorily to about -8°C (15°F) below this.

Temperature at the TR-10 point should be taken for all elastomers to determine a minimum functional temperature. In practice, a static seal may have a minimum functional temperature of about 15°C (-8°F) lower than the TR-10 point, assuming a correctly designed gland.

If the permeability rate of silicones is thought to be too high for the application, bear in mind that the rate decreases as the temperature goes down. For applications requiring moderately high temperatures as well as low, it is sometimes feasible to use two O-rings, to maintain the seal at the extreme low temperature plus a butyl or fluorocarbon to reduce permeability when the seal is warmer.

If a low temperature seal must have resistance to a fluid that attacks silicone, the answer may be a fluorosilicone. This material has excellent resistance to a wide range of fluids, is usable up to 177°C (350°F) or higher in many applications, and will often seal at temperatures as low as -73°C (-100°F). Its primary disadvantage is its lack of toughness, giving it limited usefulness as a dynamic seal, yet in certain dynamic applications, fluorosilicone O-rings have served well as springs to activate a U-type shell of fluorocarbon elastomer or other wear resistant material.

Minimum temperature recommendations are based on long term functional service. If it is subjected to this temperature continuously, it should perform reliably for 1,000 hours. Since the low limit for any compound varies with the medium, the low-temperature limit for many compounds is shown as a range rather than a single figure. It is important that you analyze all aspects of your application. Due to the variety of operating conditions and applications for these products or systems, the user, through his or her own analysis and testing, is solely responsible for making the final selection of the products and systems. Temperature should not be the only consideration when selecting an o-ring material. Media, (fluid and gas), wear, and application requirements must also be considered.

What Causes O-ring Failure At Low Temperatures?

When an o-ring is subject to low temperature cooling, it causes the elastomer to lose its elasticity - measured as the compression set. The compression set is an integral part of o-ring performance necessary to provide a reliable seal, defined as the percentage of the material that fails to return to its original size after compression. The worsening of compression set in low temperatures leads to seal leakage and ultimately o-ring failure.

Normal Recommended Temperature Range Normal recommended temperature range

Extended Temperature Range Extended Temperature Range for short term only

PDF O-Ring Temperature Range Chart

Low Temperature Fluorosilicone (FMQ, FVMQ) Compounds:

Brand Compound Number Datasheet Hardness (Shore A) Low Temp High Temp Color Recommended For
Parker Parofluor™ LA163-70 70 +- 5 -100 350 Green AMS-R-25988, TY I, CL I, GR 70, UL listed
Parker Parofluor™ LM151-50 (11645) PDF 50 +- 5 -100 350 Blue General Purpose
Parker Parofluor™ LM158-60 PDF 60 +- 5 -100 350 Blue AMS-R-25988, TY 1, CL 1, GR 60, AMS 3325
Parker Parofluor™ LM159-70 PDF 70 +- 5 -100 350 Blue AMS-R-25988, TY 1, CL 1, GR 70
Parker Parofluor™ L1120-70 PDF 70 +- 5 -100 350 Blue AMS-R-25988, TY I, CL I, GR 70, UL listed
Parker Parofluor™ L1077-75 PDF 75 +- 5 -90 350 Blue AMS-R-25988, TY I, CL III, GR 75
Parker Parofluor™ LM160-80 PDF 80 +- 5 -90 350 Blue AMS-R-25988, TY 1, CL 1, GR 80
Parker Parofluor™ L1186-80 PDF 80 +- 5 -85 350 Rust PTFE Loaded
Parker Parofluor™ 40713-75 75 +- 5 -90 350 Yellow Automotive Fuel Quick Disconnects

Low Temperature Butyl (IIR) Compounds:

Brand Compound Number Datasheet Hardness (Shore A) Low Temp High Temp Color Recommended For
Parker B0318-70 PDF 70 +- 5 -75°F 250°F Black General Purpose.
Parker B0612-70 PDF 70 +- 5 -75°F 250°F Black Vacuum, Low Compression Set.

Low Temperature Silicone (VMQ) Compounds:

Brand Compound Number Datasheet Hardness (Shore A) Low Temp High Temp Color Recommended For
Parker S0469-40 PDF 40 +- 5 -75 400 Rust AMS 3301, USP Class VI, A-A-59588 CL2a, 2b, GR 40
Parker S0802-40 PDF 40 +- 5 -60 400 White FDA
Parker S0595-50 PDF 50 +- 5 -70 400 Rust AMS 3302
Parker S0899-50 PDF 50 +- 5 -103 400 Rust ZZ-R-765 CL 1a, 1b, 2a, 2b GR 50
Parker SA150-50 50 +- 5 -65 400 Trans Low Organic Extractibles
Parker S0317-60 PDF 60 +- 5 -103 450 Rust FDA, USDA, USP CL VI
Parker S0613-60 PDF 60 +- 5 -60 450 Rust ZZ-R-765 Cl 2b, Gr 60, AMS 3303
Parker S0383-70 PDF 70 +- 5 -175 400 Rust A-A-59588 CL 1a, 1b, GR 70, AMS 3337
Parker S0455-70 PDF 70 +- 5 -65 450/500 Rust High Temperature
Parker S0604-70 PDF 70 +- 5 -65 450 Rust ZZ-R-765 Cl 2a, 2b, Gr 70, AMS 3304, AMS 3357, MIL-G-21569 Class 2
Parker S1138-70 PDF 70 +- 5 -60 400 Rust FDA, USP Class VI, USP <87>
Parker S1224-70 PDF 70 +- 5 -65 450 Rust A-A-59588 Cl 2a, 2b, Gr 70, AMS 3357, MIL-G-21569 Class 2, AMS 3304
Parker SM355-75 PDF 75 +- 5 -60 450 Rust AMS 7267, FDA, USP Class VI, USP <87>
Parker S0614-80 PDF 80 +- 5 -65 450 Rust A-A-59588 CL 2a, 2b, GR 80, AMS 3305
Freudenberg 78 VMQ 166898 PDF 78 +- 5 -- -- Light Blue
Freudenberg 75 VMQ 176643 76 +- 5 -- -- Red
Freudenberg 70 VMQ 117055 PDF 70 +- 5 -- -- Transparent