ABBREVIATIONS, PREFIXES, AND LETTER SYMBOLS

amp

ampere

ARP

Aeronautical Recommended Practice

ASLE

American Society of Lubrication Engineers. Changed now to Society of Tribologist and Lubrication Engineers (STLE).

ASME

American Society of Mechanical Engineers

ASTM

American Society for Testing Materials

ANSI

American National Standards Institute

atm

atmosphere

BTU

British thermal unit

C or cent.

centigrade

cc

cubic centimetre

cm

centimetre

cfm

cubic feet per minute

GPM

gallons per minute

hp or HP

horsepower

HVI

High Viscosity Index, typically from 80 to 110 VI units.

Hz

Hertz (cycles per second)

ISO

International Standards Organization, sets viscosity reference scales.

JIC

Joint Industry Conference

kg

kilograms

km

kilometre

kHz

thousand Hertz (cycles per second)

log

logarithm (common)

LVI

Low Viscosity Index, typically below 40 VI units.

MIL

military

M

meter

µm

micron (micro-meter)

NFPA

National Fluid Power Association

NEMA

National Electrical Manufacturers Association

NEC

National Electrical Code

NAS

National Aerospace Standard

NASA

National Aeronautics and Space Administration

psi

pounds per square inch

psia

pounds per square inch absolute

rpm

revolutions per minute

SAE

Society of Automotive Engineers, an organization serving the automotive industry.

SSU

Saybolt Universal Seconds (or SUS), a unit of measure used to indicate viscosity, e.g., SSU @ 100° F

STLE

Society of Tribologist and Lubrication Engineers, formerly ASLE, American Society of Lubrication Engineers.

PPM

parts per million (1/ppm = 0.000001). Generally by weight. 100 ppm = 0.01%; 10,000 ppm = 1%

Q

flow rate - GPM

t

time in seconds

P

pressure drop psid

T

temperature change, Fahrenheit

total volume (gals)

PREFIXES

kilo

Thousand

mega

Million

centi

Hundredth

milli

Thousandth

micro

Millionth

CLEANLINESS DEFINITIONS

Clean? 100 particles >10 micron per millilitre

Super clean? 10 particles >10 micron per millilitre

Ultra clean? 1 particle >10 micron per millilitre