Mobile Catering Trailers

Catering Trailers

Mobile Catering Trailers

N4 Gas is one of the few companies in London that offer testing, certification and modifications to mobile catering units that utilize bottled gas as a cooking or hygiene fuel. When you log a call for one of our Gas Safe Registered mobile catering engineers; you’ll be in good hands. Especially when you consider that we have supplied services to clients that trade at some of the biggest events in London, as well as specialist trailer conversions for film sets and general street trading.

This article aims to resolve some of the legal jargon, requirements and minimum standards that all catering trailers are required by law to comply with. Unlike gas that is supplied to your home, bottled gas is incredibly potent and has a higher energy rating than that supplied through the pipelines to homes and businesses throughout the UK.

Bottles & bottle sizes

Bottled gas comes in two variants; Propane and Butane. Easily identified by Butane being distributed in blue gas bottles and Propane in red gas bottles. Each type of gas is available in several bottle sizes, measured by their weight rather than physical space requirements. The bottle size is not just about how long the gas will last; it also provides a suitable flow of gas, if you have a small bottle running a large appliance, the gas will not be able to boil fast enough and keep up with the demand made by the appliance, causing poor combustion and possibly a dangerous situation.

This is normally easily identified when bottles start to “Freeze” on their exterior, although our engineers will be able to calculate the correct bottle size(s) for your installation after a quick assessment of your intended use. It’s imperative that only bottles big enough to do the job are employed and will be part of the certification process.

It’s also important to note that the fuel’s are different; Butane should only be used for appliances designed to run on Butane and Propane should only be used for appliances that are designed to run on Propane. This will always be stated within the appliance manufacturer’s instructions, but will often be marked on an appliance (Unless it’s worn off over time), a general rule of thumb is that Propane is used in commercial environments and Butane for domestic purposes (Like the household BBQ). All owners of mobile catering units must be running Propane with a Screwed bottle connection.

When the installation is on a vehicle, bottles must be stored in a rigid chamber that has no access from the interior serving area of the vehicle with an isolation valve for every appliance and a singular isolation valve that can turn off the gas supply from within the vehicle; plus the additional form of isolation on the bottles themselves and more than likely on the changeover valve. For larger installations; a changeover valve is essential to ensure that when a bottle runs low, gas can be swapped to a second bottle with minimal fuss.


All mobile catering units that burn gas require a permanent form of ventilation (And we unfortunately do not count the serving hatch as ventilation) – This will need to be in the form of a physical hole in the skin of the vehicle to the outside air – Often found fitted to the doors, roof or floor of the vehicle and allows the gas appliances to burn safely in the event that they are used with the serving hatch closed – Which, by the way, we strongly advise against. Our engineers will be able to advise you of ventilation requirements at the time of any inspection.


Mobile Catering Inspection’s carried out by our engineers are valid for 12 months from the time of inspection. However; inline with the codes of practice issued by UK-LPG, we strongly advise re-testing at 6 monthly intervals and our paperwork States this. This is primarily due to the fact that trailers often get dragged about fields and joints can become loose and will often need tightening, remaking or just checking over at much sooner intervals than static vehicles or premises. If you currently have a standard “Gas Safety Record” issued for your catering trailer; then it is effectively void as it does not cover the legal testing requirement for such vehicles.

We test a lot of trailers within London and some key points that you should note before our engineers come to test your vehicle are:

  • You must have gas, and enough gas for us to run your appliances for upto 30 minutes each
  • You should have a working power supply for lighting
  • You have the legal right to park your vehicle where it will be worked on
  • The vehicle has a registration number and/or a legible chassis plate
  • All gas appliances are firmly fitted and in working order (If not, just let us know when you phone)

Please note that under no circumstances do we carry fuel bottles. We do carry a limited amount of spares, but if you know that you have any issues (Like flexible connections being older than 5yrs) please inform us so that we can make arrangements to bring along a larger stock selection.

Need to book a test? Contact us on 0208 348 4729.