6 things to consider when designing office plumbing

Nov 20

At Southern Energy Solutions, we can carry out all kinds of plumbing work for the commercial sector.

It seems obvious to us therefore that no two projects are the same, and that designing plumbing or heating systems for a shop is different to designing systems for an office building.

In fact, offices (and in particular high-rise office buildings) can present challenges to the design and installation of a plumbing and heating system that are totally unique.

If you are working on this kind of project then it is critical that you consider what these challenges are and get the best advice as to how to overcome them.

Let’s run through what some of those challenges are.

1. Water Pressure

The typical mains water supply runs at 10 metres head (approximately 14 psi or 1.0 bar) which is powerful enough to fill a 2 litre bottle in about 13 seconds.

That 1.0 bar is the force needed to raise water to a height of ten metres, and so for buildings taller than the average two-storey home, you will either need a written guarantee that the pressure will be sufficient to pump water to the top-most storey of your building, or you will have to boost the pressure yourself.

You can do this using several different techniques (including booster pumps or gravity tanks) but if doing so you’ll need permission from the water authorities.

2. Drainage

One thing to consider when water is travelling down a vertical pipe (as it does when being drained out of a high-rise building) is that the water tends to stick to the side of the pipe, which creates an inner pocket of air.

The water travels at around 15 fps (feet per second) and whilst the pipe remains vertical, that pocket of air is harmless. However, when the pipe changes to horizontal, the water flow slows to around 4-8 fps, creating a backlog of water that compresses that air.

This means that you’ll have to install a series of “relief vents” at regular intervals to equalise the pressure.

3. Venting

As mentioned above the build-up of air pressure in drainage pipes needs to be counteracted. When water in a pipe flows into a lower area, air must be added to replace the water, or a negative pressure zone will occur.

If this occurs near a fixture (i.e. a sink), air will be drawn into the drainage system through the fixture trap – which causes a “gulping” or “gurgling” sound.

To prevent this, relief vents need to be attendant, which will allow for pressure equalisation and relief across the whole system.

4. Hot water systems

Dual supply systems are those in which two different grades of water are available in separate piping systems. An example is a sink supplying water directly from the incoming water service while other fixtures are fed from a storage tank.

Most commonly this secondary supply comes from a hot water tank and is piped separately to the cold water.

For buildings with around 28 floors, there should be two different heating systems serving half the building each. This means you would need to install a heat exchanger either in a sub-station on the ground floor, or a separate sub-station on the 15th floor.

A heat exchanger transfers heat from one fluid to another without the two ever coming into contact.

How many will you need in your system?

5. Vertical Piping

Generally, in multi-storey projects, vertical piping is a better option than horizontal piping because it uses fewer supports, hangers and inserts and requires less space.

Using horizontal pipes also has implications for water pressure as mentioned earlier, as vertical piping ensures the water moves around that 15fps mark.

Choosing between the two is crucial before you ask a plumbing company to design the system.

6. Fire protection

Have you thought about what your fire protection system will look like? While not a legal requirement (unless your fire risk assessment says it is!) the safety of your staff should be a primary concern when designing the building.

If it turns out that you do need a sprinkler system (or you just install one because you want one) the fire sprinkler heads are added at regular intervals according to the BS9251, while the sprinkler system pipework would then need to be connected either to a direct water supply from the mains or from a water storage tank with a fire pump set.

Are you looking for a professional, experienced company to design a plumbing and heating system for your new offices?

Southern Energy Solutions have completed office fit-outs across the South East, and we can undertake all aspects of the plumbing and heating work on-site, including:

  • first and second fix tea points
  • Male and female toilets
  • Disabled toilets
  • Cleaning sinks

We can price your project directly from your plans without needing to visit the site – which means we can get your project underway as soon as possible. We can also either supply and fit all the necessary parts or fit parts that you supply. You will get a dedicated site manager who will deal with you directly and answer any questions you may have about progress of works.

To get started, please contact us here.