Filtration Abbreviations Explained: A to I

Everyday at Classic Filters we use abbreviations to save time and space in documentation for manufacturing filters, but lots of people ask the question “what do they mean” and do you personally know what they all mean?

Well we have decided to shed some light on the situation and give you a helping hand by explaining what they mean.

As there are so many different abbreviations we have decided to talk about the topic in two posts. This post will take you from A to I and let you absorb this round of terms.

If you know one we have missed or want to know one we have missed then leave a comment below and we’ll update the list. How big will the list become?!


ANSI – American National Standards Institute

API – American Petroleum Institute

ASME – American Society of Mechanical Engineers

ASSY – Assembly

ASTM – American Society of Testing Materials

AVG – Average


BB – Bolted Bonnet

BC – Bolt Circle

BF – Blind Flange

BLDG – Building

BM – Bill of Material (Also BOM)

BOP – Bottom of Pipe

BSI – British Standards Institute

BW – Butt Weld


CI – Cast Iron

CO – Clean Out

CONC – Concentric

COND – Condensate

CPLG -Coupling

CS – Carbon Steel or Cast Steel

CSC – Car Sealed Closed

CSO – Car Sealed Open


°C – Degrees Celsius

°F – Degrees Fahrenheit

DI – Ductile Iron

DIA – Diameter

DWG – Drawing


ECC – Eccentric

ELEV – Elevation


FF – Full Face

FIG – Figure

FLG – Flange

FOB – Flat on Bottom

FOT – Flat on Top

FS – Forged Steel

FT – Feet or Foot

FW – Field Weld


GALV – Galvanized

GR – Grade


HDR – Header


ID – Inside Diameter

INS – Insulate

INV – Invert (Inside Bottom of Pipe)

IPS – Iron Pipe Size

I-ST – Insulate and Steam Trace

Don’t forget to come back next week and see the next list of manufacturing/engineering abbreviations L to X.

As a filter manufacturer we hope this has been some service to you. If you have any further question or have any filter problem then do not hesitate to  contact us by calling +44 (0)1634 724224 or send us an email to [email protected]


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