An enclosed space for entrance between an outdoor gas dangerous zone on open deck and a gas safe space, arranged to prevent ingress of gas to the gas safe space.

An innovative concept of reducing hull friction by means of air lubrication. A layer of air is generated between the specially profiled underside and water surface, so that the vessel effectively glides through the water, reducing drag by 5-15%.

The air mass coefficient is commonly used to characterize the performance of solar cells under standardized conditions, and is often referred to using the syntax "AM" followed by a number. "AM1.5" is almost universal when characterizing terrestrial power-generating panels.

A pipe provided to equalize the tank pressure with the atmospheric one while the tank is being emptied or filled. Air pipes terminating on the open deck shall be fitted with approved air pipe heads.

Air pollution is the presence of substances in the atmosphere that are harmful to the health of humans and other living beings, or cause damage to the climate or to materials.

Air quality laws govern the emission of air pollutants into the atmosphere.

A pressure vessel for storing compressed air. Air receiver is built and tested similarly to aboiler drum.

That part of a ship resistance to motion that is due to the resistance of the air to above-water portion of the ship moving throught it.

An air source heat pump is a type of heat pump that absorbs heat from a colder place and release it into a warmer place using the same vapor-compression refrigeration process and same external heat exchanger with fan as used by an air conditioners.

Parts of the hull that may either itself be used to conduct air or which contain air ducts as well as other lines (pipes, cables).

Airborne wind energy is the direct use or generation of wind energy by the use of aerodynamic or aerostatic lift devices.

Airborne Wind Energy Industry Association (AWEIA) was founded in 2009 to serve globally companies and institutions dedicated to converting wind energy for useful loads (airborne wind energy technology) by use of tethered and free-flight aircraft.

A wind turbine that does not require a mast but is tethered to the ground or a floating pontoon. The tethers require a means to conduct the electricity to the ground.

Paints which dry and form a film while exposed to air. Oil and alkyd paints are usually air-drying.

The shape of the blade cross-section, which for most modern horizontal-axis wind turbines is designed to enhance the lift and improve turbine performance

Air–fuel ratio is the mass ratio of air to a solid, liquid, or gaseous fuel present in a combustion process.

Air-fuel ratio is the mass ratio of air to fuel present during combustion.

A method of paint spraying which does not use compressed air to atomise the paint.

An airshed is a part of the atmosphere that behaves in a coherent way with respect to the dispersion of emissions.

A visual and/or audible signal indicating an abnormal situation.