Natural Gas to Floating Building

[PEDARRIN2]

Has anybody designed a natural gas service (1-2 psig) to a floating building (basically a heated storage building for fire department boats) on a river bank?

Have a building with some gas heat and a generator where the gas service is on land above 100 year flood stage. Has a walk way, which is below the 100 year flood stage to the building where the generator and heaters are located.

Planning on running hose, similar to what is used on propane grills, only more sturdy and rated for natural gas and the pressures involved.

Issues include whether to run full pressure to generator and regulate at the generator to ~11" w.c. or run lower pressure (larger hose)to both building and generator. Have had issues sending lower pressure gas to generators because of the initial start up. But do not really want to send the higher pressure in a hose. Will have excess flow valves at the source to shut off flow in the event of a hose break. Also want to give the fire department the ability to shut off gas to the building while maintaining generator operation.

I know what I would do if this building was on land, but have no idea of what is commonly done for floating buildings.

Really appreciate any help that can be given.

 

[catserveng]

A few years ago I did an installation and startup on a natural gas powered genset (250 ekW) and two gas engine driven fire pumps (200 bhp) on a floating pier. The piping was run in Schedule 40 stainless steel pipe with natural gas rated high pressure hoses with fire sleeve at the flex points, which were at the top and bottom of the ramp. The local Fire Marshall limited hose length to no more than 4 feet (not sure how he came up with that number but he was the AHJ). A riser pipe and emergency shutoff valve was installed at the head of the ramp to shutoff all gas to the pier.

According to my notes, the pressure at the engines was 4 PSI (running at full load), each unit had a pressure regulator, the pressure at the head of the pier was 6 PSI. It was a commercial pier so everything was overbuilt, but I did a site visit for some maintenance a year later and there were no reported problems with the fuel system. Only change was a locked cage with a fire department keyed lock on the emergency shutoff valve at the head of the pier, seems someone at some point messed with the valve.

I think your local codes and AHJ's will likely be the driving force in how you actually make the installation. Hope that helps,

MikeL.