Standards in generator exhaust systems don’t restrict the design of manufacturers as long as it is safe, practical, economical, and effective.

The exhaust system requirement under the National Fire Protection Association in Paragraph 7.10.4.5 of the NFPA 110 publication also known as Standard for Emergency and Standby Power Systems states that –

“For reciprocating engines, the piping shall terminate in any of the following:
(1) Rain cap
(2) Tee
(3) Ell, pointing downwind from the prevailing wind
(4) Vertically upward-oriented stack with suitable provisions for trapping and draining rain and snow water.”

While some generator set muffler ends are terminated with a rain cap, using this generator outdoors would still catch rainwater while in operation. Buyers of this generator must ensure that the muffler is self-draining. The muffler drain should be regularly checked during maintenance. It should be clean and free from debris to allow self-draining.