ACM - polyacrylate rubber

ACN - acrylonitrile; component in nitrile rubber

AISI - American Iron and Steel Institute

ASTM - American Society for Testing and Materials

DIA - diameter

DRO - dynamic run-out

FDA - Food and Drug Administration

FEPM - tetrafluoroethylene-propylene rubber

FKM - fluoroelastomer

FPM - feet per minute; used as a measure of surface speed at the contact point between a seal and the shaft

HNBR - hydrogenated nitrile rubber

HSN - highly saturated nitrile; alternative name for HNBR

ID - inside diameter

IN - inch

IRHD - International Rubber Hardness degrees

IRM - Industry Reference Material, as in IRM 903 oil

ISO - International Organization for Standardization

KN/M - kilonewtons per meter; SI equivalent of pli; sometimes a unit of measure in ASTM D 2000 line call-outs

LOP - lip opening pressure

MAX - maximum

MDR - moving die rheometer

MIN - minimum

MPA - megapascal; SI equivalent of psi; sometimes a unit of measure in ASTM D 2000 line call-outs

NBR - nitrile butadiene rubber (Buna N); copolymer of acrylonitrile and butadiene

NBS - National Bureau of Standards

NSF - National Sanitation Foundation

OD - outside diameter

ODR - oscillating disk rheometer

OOR - out-of-roundness

OSHA - Occupational Safety and Health Administration

PLI - pounds per linear inch

PSI - pounds per square inch

PTFE - polytetrafluoroethylene; a fluoroplastic

RA - roughness arithmetic average in surface measurements

RMA - Rubber Manufacturers Association

RPA - rubber process analyzer

RPM - revolutions per minute; also the average peak to mean height in surface measurements

RWD - radial wall dimension

RWV - radial wall variation

RZ - average peak to valley height in surface measurements

SAE - Society of Automotive Engineers

SG - specific gravity

SI - denotes The International System of Units (the modern metric system); taken from the French, “Le Système International d’Unités”

SPEC - specification

STBM - shaft-to-bore misalignment; phenomenon in which the shaft and the bore do not share a common center

TIR - Total Indicator Reading

UV - ultraviolet light

VMQ - vinyl methyl silicone rubber

“This list includes the abbreviations you will encounter most often in the sealing industry. Familiarity with them will save time as you select or design shaft seals.”