For a static crush seal application, it is recommended that the o-ring volume does not exceed 95% of the gland void.
For reciprocating seals – passing o-rings over ports is not recommended. Nibbling and premature wear and seal failure will result.
The closer the application is to room temperature, the longer an o-ring can be expected to effectively seal. (Seal Types & Gland Designs – Rotary Seals)
Avoid using graphite-loaded compounds with stainless steel, as they tend to pit the stainless steel surface over time. (Seal Types & Gland Designs – Surface Finishes)
Before o-ring installation, make sure to lightly coat the o-ring with a lubricant that is compatible with the o-ring material, as well as with system chemicals.
When using only one back-up ring, be sure to install it on the low pressure side of the o-ring. (Environmental Factors – Seal Compression)
Static seal cross sections are generally compressed from 10% to 40%, whereas Dynamic seals are from 10% to only 30%. (Environmental Factors – The Effect of Friction)
When it is said that an elastomer is good for an application it is meant that some compounds which include that material are acceptable, not all. For instance, some compounds of EP are good for brake fluid applications, but most are not acceptable. (Material Selection Guide – Fluorosilicone)