Propane is ______ than air

The primary air is admitted at a ratio of about _______ parts primary air to 1 part gas for natural gas

The Bunsen burner flame is practically nonluminous

When burning natural gas, the air adjustment is generally made to secure as _____ a flame as possible.

______ on pipes and pipe fittings should be located by spreading a soap solution over the surface:

Aluminum tubing or castiron fittings should be used for the main gas line.

During incomplete combustion which of the following is produced:

The burner tube of an ________ is commonly a straight, adjustable venturi that extends horizontally from the unit

Install the main manual gas shutoff valve on the riser at least _______ above the floor level

Natural gas has a specific gravity of _____

A yellow flame indicates dependence entirely on ______ air for combustion

The maximum allowable concentration of continuous 24hr exposure of Carbon monoxide according to ASHRAE is about ______:

A draft hood is used to ensure the maintenance of constant lowdraft conditions in the combustion chamber with a resultant stability of air supply

OSHA standards prohibit worker exposure to Carbon monoxide not more than _____ PPM air averaged during an 8 hour period:

Which of the following gas is the main constituent in Natural gas: