Ask the Expert Question-and-Answer Archive

by Ron Joseph

September, 2002

Do Regulations Ban the Use of Conventional Siphon-Feed Spray Guns?

Q. Is there a federal regulation that prohibits the use of a conventional, siphon feed spray gun?

A. I am not aware of any Federal or state regulations that directly and specifically ban the use of conventional siphon-fed spray guns.

There are regulations, Federal and state, that only permit the use of HVLP and electrostatic spray guns, where "HVLP" is defined as a gun for which the atomizing air pressure does not exceed 10 psig. I cannot give you a comprehensive list of the rules, but for starters you can look at the Aerospace NESHAP (Federal), and the surface coating rules in California, (South Coast AQMD, Bay Area AQMD, San Diego APCD, and most of the other districts in the state.)

These rules do not mention the use of conventional, airless or air-assisted airless guns, because it is assumed that they do not meet the definitions of electrostatic or HVLP. Therefore, if you want to use a conventional siphon-fed spray gun and can demonstrate that the atomizing air pressure at the cap of the gun does not exceed 10 psig you can presumably argue that the gun meets the definition of HVLP, even though it doesn't carry the name "HVLP" on the handle or in the product literature.

Here is a problem that I can foresee. If an inspector comes into a paint facility and finds a painter using a conventional siphon-fed spray gun, but the painter does not own a pressure gauge/cap kit to demonstrate the 10 psig requirement, the inspector has the right to issue a Notice of Violation. On the other hand, if the painter is using a genuine HVLP siphon-fed spray gun, yet he does not own a measuring kit, it is quite possible that the inspector will simply assume that the painter is in compliance. As you well know, a painter can easily take an HVLP gun out of compliance by increasing the air pressure to the gun, but most inspectors are not aware of this.

When I teach my classes to the industry I take no chances. If the painters fall into a rule that regulates HVLP, I advise them to replace their conventional guns with HVLP. Once the painters leave my classes, I no longer have any control on them. Since painters tend to teach each other, any information that I teach in class gets to be diluted and distorted as time goes by. One or two generations of painters down the line, many of the explanations I gave during class are no longer remembered.

In summary: I am not aware of any regulations that specifically and directly outlaw the use of conventional siphon-fed spray guns.

There are several regulations that regulate the use of HVLP spray guns.

If a conventional siphon-fed gun is being operated with an atomizing pressure that does not exceed 10 psig, you might be able to argue that the gun meets the definition of HVLP and should be considered to be legal. There is no guarantee that the federal or state agency will buy this argument.