NACE MR0175: Material Selection for Sour Gas (H2S) Resistance.

Material Selection for Sour Gas (H2S) Resistance

Problem Statement

Rubber seals in sour gas environments face chemical degradation due to hydrogen sulfide (H2S) exposure. Standard elastomers like NBR exhibit swelling, cracking, and loss of mechanical properties at elevated temperatures and pressures.

Material Science Analysis

H2S reacts with unsaturated polymer chains, causing chain scission and crosslink degradation. Fluorocarbon elastomers (FKM) resist H2S due to their high fluorine content (66-70%) and stable carbon-fluorine bonds. HNBR offers intermediate resistance but lacks FKM’s thermal stability above 150°C.

Technical Specs

• Material: FKM (Grade: Viton® GLT-S)
• Shore A Hardness: 75 ± 5
• Tensile Strength: 18 MPa
• Elongation at Break: 200%
• Temperature Range: -20°C to +200°C
• Compression Set (22 hrs @ 200°C): 20%

Material Comparison

Parameter	FKM (Viton® GLT-S)	HNBR (Therban® 3447)	NBR (Nipol® 1042)
H2S Resistance	Excellent	Good	Poor
Temperature Range (°C)	-20 to +200	-30 to +150	-40 to +120
Compression Set (%)	20	25	35
Shore A Hardness	75 ± 5	70 ± 5	65 ± 5

Standard Compliance

RubberQ’s IATF 16949-certified process ensures batch traceability and compliance with ASTM D2000 and ISO 3601. PPAP documentation includes material certifications, process flow diagrams, and control plans. Every batch undergoes adhesion testing per ASTM D429 and cleanliness inspection per ISO 16232.

For custom material compound development or IATF 16949 documentation, consult RubberQ’s engineering department.