Mobile shower cubical

[R.P.McMurphy]

Hi, i have a small toilet trailer with 2 toilets cubicles, id like to turn one of the cubicles into a shower cubical. Both areas are completely separated as one was for male and one was for females.

Id like to be able to use the shower with just a hook-up through an extension lead or a generator, and a hose pipe to supply the water.

how's the best way to install a shower? and what kind. Hotwater tank, pump and thermostatic shower? are there electric showers that could run on a 13a socket? what about having instant heated water, using a gas bottle? (though I'd prefer not to have to go to that trouble.) any ideas chaps?

cheers

Steve

[Harry Bloomfield]

R.P.McMurphy expressed precisely :

I'm not clear on the purpose, how frequently you intend to use it, nor who is intended to use it, however....

Many years ago, before caravans were equipped with showers, I used a rather neat portable shower. It comprised a shower curtain hanging from its metal frame, a plastic fold up base to collect the water and a pump up sprayer. The later is the interesting bit....

It was broadly similar to one of those pump up to pressurise garden sprayers. You fill them with a couple of gallons or so of water, pressurise it with a pump and away you go pressing a button to release the spray water. The only difference was the spray head and the fact that you filled it with warm water to suit your needs. A garden sprayer would work for this purpose fine, if you can improvise the rest.

[Owain]

You will only get a handwash spray (and a fairly feeble one at that) from 3kW.

Seriously, I think your only options are (a) stored hot water (probably electric), or (b) instantaneous gas. If you have a fixed electric mains supply at the location then electric may be an option, but many temporary supplies won't cope with a sustained 3kW / 13A load.

Caravan and boat suppliers will be your friends.

Owain

[R.P.McMurphy]

am a member of a car club and our shower facilities at some events are non existent or poor. I bought this trailer toilet to provide a better experience for the ladies who accompany their chaps to our events..i.e. a decent shower and toileting experience!

I'm leaning towards using a gas fired domestic hot water heater, supplied via a cheap 1 bar pump from a cold water tank. that way i can guarantee a stable flow to the heater and shower. the toilet and the tank can be supplied directly from the hose mains. Any thoughts on that?

Steve

[meow2222]

A few more choices too:

1. 2x 3kW heaters, which you have to ensure are plugged into different ring circuits in a domestic situation - its doable, but will need a bit of electrical savvy to operate reliably. 6kW would give an adequate instant heated shower, though nothing marvellous.

1. Hot water tank with either 3kW element or 2x3kW element for faster heating

2. Solar heated tank, fine in summer, but water will not be hot at dawn of course. Adding fold-out reflective flaps would increase heating speed and temp. Using a separate fold-down hosepipe heating coil would really boost heat harvest - you could have decent shower power in summer this way.

1. Liquid or solid fuel heating, either instant or stored heat. Instant can be 6-20kW, for stored 3kW would be adequate. Paraffin heating is relatively cheap.

2. Plug into someone's hot and cold taps using clamp on connectors on long hoses.

1. No on-board heating, just fill the tank up from someone's hot tap and insulate the tank.

In several cases you wouldnt need any electricity connection - which is a good thing on the whole, as electrical safety will complicate things. If you need leccy just for an overheat safety cutout, eg with solid fuel instant heating, you could do that at 12v, sidestepping all the usual mains - outdoor - shower electrical safety issues.

NT

[R.P.McMurphy]

I'd prefer a system that is versatile and requires as little intervention as possible and capable of providing a near continuous flow of showerees(assuming 5 minute gaps between showers). So no to options that will require intervention other than daily cleaning and stocking up of bog roll. I'm thinking of using a 1000ltr water tank filled by a ballcock from the hose supply. then take a 22mm water feed to a single impeller pump to a gas instant water heater then out to the shower head. or take 2 pipes to a twin impeller pump, one of the outputs to a instant water heater then to a thermostatic shower valve and the other pump out put straight to the thermostatic shower valve.

foresee any problems here anyone?

Steve

[Owain]

And the safety considerations of a trailer full of paraffin? Remember, this trailer has to be insured for use on the road.

Owain

[Owain]

If you can provide sufficient flow for the boiler by using an external diesel-fueled pump, or use a pressurised storage vessel pumped up by a footpump before each shower, you could probably do without electricity at all as some gas water heaters can operate without it - check Main Multipoints.

Owain

[meow2222]

That rules out relying on the host houses's hot water supply then. And temperamental sources like solar and solid fuel.

If youre using instant heating you wont need a 1 ton water tank. Just enough to let the heater shut down gracefully if the waste supply stops and thus pressure falls. That means you could put your 25kg tank high up, and lose the pump. Fold it down when driving.

If you use pumping you need leccy, which means a local CU with RCD and earth spike, plus you've got all the regs that apply to temporary installations then. The requirement foe safety inspection at every installation time could be a problem. Plus your host has to have mains power always, and not be worried how much you'll cost them etc.

I guess your gas heater should have its overheat cutout temp changed to something safe for showering. A 90C cutout - and the temp will rise uncontrolledly when water runs out - would be dangerous.

A small mixing tank on the heater output would safely absorb the heat in the heat exchanger when water supply cuts out. Mixing the small amount of hot with a larger amount of warm would much reduce any temp rise.

NT

[John Stumbles]

DC

[R.P.McMurphy]

electricity is not a problem, both our main sites have somewhere you can plug an extension lead in, and the trailer already has the electrics fitted. I'm not gonna need to put an earth spike down when sited am i?

good point about the temp output of the boiler, shouldn't be a problem changing the max temp cut off. also, i would imagine most water heaters will shut down wit out flow?

Steve

[meow2222]

AFAIK its legal to carry a jerry can in a vehicle or trailer. A trailer full of paraffin would certainly make for a lot of showers :) But yes it may be necessary to drain the heater back to the can if this is used. Paraffin heating would certainly be a relatively cheap option, but I'm not sure how one would arrange any required safety features. Maybe a thermostatic shower would be enough to protect the user against overheat, and an open heat exchanger enough to prevent heater damage. Then again the overheating of a sheet of corrugated steel doesnt sound a particularly costly fault scenario.

Oh, gotcha: a drain heat exchanger would reduce your heat input requirement considerably. And it would be relatively simple to make.

NT

[Owain]

Quite probably; you are not allowed to export PME earth to 'caravans' (which I think is what your trailer will count as in terms of an electrical installation) and you may need an earth spike anyway depending on the earth impedance of the existing installation (which you have no control over) and the length of your extension lead.

It could be *very* nasty if someone steps from trailer earth to local earth and there is a significant potential difference zipping up one leg and down the other.

You will have public liability insurance for this contraption won't you?

Mobile trailer showers are made, eg for on-site asbestos decontamination

- have a look at what they do.

Owain

[Owain]

Some ideas:

You can hire heated decontamination showers from HSS

portable shower (US) diesel water heaters water heaters for caravans

[R.P.McMurphy]

i cant see that this will need an earth spike, because caravans don't need them.

i will look into PLI, it may come with the clubs own insurance package.

The toilet block is almost entirely wood. in the toilet as it stands now there are no metal items other than the flush handle and door bolt. the chassis is the only other thing metal. currently there is an electrical lead serving a couple of light bulbs. so it looks like i need to fit a proper system, i suppose a simple CU will suffice; earth the chassis, power the lights and a saniflo, a submersible pump and a boiler. Possibly might add a fan heater that comes on when a PIR detects someone in the toilet or shower and below a certain temperature.

Steve

[meow2222]

Where does a saniflo come into this? Whats your drainage arrangement?

NT

[R.P.McMurphy]

I'm gonna use a saniflo to mush the crap up and pump it either to a nearby manhole (foul waste) or into a IBC 1000 litre tank as recommended by a mate. then it can be used in store mode or continuous mode. to empty the tank the trailer will need to be towed to a nearby manhole cover and discharged via gravity and the 4" pipe. The shower and hand wash basin can also be plumbed into the saniflo to simplify things. i was thinking of using a commercial version of the saniflo...hopefully that will cope better with any junk flushed away by women.

Steve

[meow2222]

you seem awfully optimistic about saniflos.

[R.P.McMurphy]

yep, i know they are not fault free, but the commercial version, sanibest, is more rugged and can cope with ST's ect whereas the domestic version cannot. It also provides a solution to moving the toilet waste from the back of the toilet to a large storage tank and also the facility to enable the muck to be conveniently pumped to the nearest manhole. it can also cope with the output of the shower. also chops the shit up so it can be pumped through a hose. simple and effective i hope. we will see!

Steve