Refrigeration & HVAC Design Support – PRV Line Sizing

As a specialist design company, ODA recognise that not all refrigeration and HVAC contractors will have in-house design.  Regardless of the project size we are here to support contractors and client alike, to ensure systems are designed correctly.

In the first of our design insights, we want to focus on the Heat Pump market, which is a rapidly growing sector.  There are key areas of design that suppliers will need support with.  A good example being being PRV line sizing and selections.  We have successfully selected suitable upstream or downstream PRV line sizing, material, and gauge selection for our customers.

To meet F-Gas regulations, low global warming potential (GWP) refrigerants are being used in both refrigeration and comfort heating/cooling applications. These refrigerant types range from A1, A2L, and A3. Each having their own safety requirements to meet regulations and British Standards.  To conform to BS EN378, some refrigerants and specific applications require the safe removal of refrigerant to the outside should the pressure relief valve open.

To select pipework, we must comply with the calculations set out in BS EN13136.  This takes into account the available pressure drop when selecting a suitably sized pipe diameter, but also considering the refrigerant properties, pipe material, number of bends, and connection types.

Some of the examples of questions we get asked include;

• What if we relocate the PRV to the outside?
• What if the PRV length is reduced?
• What if we vented in the plantroom?
• What if the plant is location outside?
• What if we reduced the number of bends?
• What if we used a different refrigerant?
• What if the supplier provides a different pressure relief valve?

Whatever questions you may have, we have the experience to offer a response and support in finding the correct answers for each project application.

If you need help with line selections and installation guidance, CAD, or BIM support, or if we can help with your application requirements and responsibilities, then please get in touch.