Type I. A primary tank wrapped by an exterior shell that is in direct contact with it. The exterior shell might or might not wrap the 360 circumference of the primary tank.

Type II. A primary tank wrapped by an exterior shell that is physically separated from it by stand-offs and that wraps the full 360 circumference of the primary tank.

A

AA (arithmetic average)

A numerical measure of metal surface roughness.

ABS

Acrylonitrile butadiene styrene.

absorption

The soaking up of a gas or liquid into a solid substance.

ac

Alternating current.

acfm

Actual cubic feet per minute for compressed or vacuum air.

actuator

A movable component of a valve that when operated, causes the closure element to open or close.

adsorption

The condensation of gas or liquid onto the surface of a solid.

AEC

Architect, engineer, and constructor.

aerobic

Bacteria requiring free oxygen for their growth.

aerosol

Particles, solid or liquid, suspended in air.

aftercooler

In compressed-air service, the aftercooler is a device used to lower the temperature of the compressed air immediately after the compression process.

AI

Aggressiveness index (a guideline parameter to find the corrosive tendency of potable water).

air gap

An unobstructed separation between a source of potable water and any source of contamination.

AISI

American Iron and Steel Institute.

anaerobic

Bacteria living in the absence of free oxygen, deriving it instead from breaking down complex substances. Bacteria requiring...