Part L revision mandates annual check of heating systems for cleanliness & inhibitor levels plus fitting a filter

Building Regs, Part L and BS7593 Update: your questions answered

Some information published in this article has since been revised. Please see the updated article here.

Following a consultation period, Part L of the building regulations, has recently been updated and is due to go live very soon. The main change for Sentinel customers and users concerns the status of BS7593, which is the 'Code of practice for the preparation, commissioning and maintenance of domestic central heating and cooling water systems'.

What do the changes mean and what do they mean for me?

A summary of the main points, changes and how Sentinel can help you meet compliance can all be found below.

The changes

The Ministry of Housing, Communities and Local Government (MHCLG) has published 2 Building Regulations updates, which apply to England. These are split across domestic and commercial properties.
On a domestic level, following the consultation on Part L amendments, there has been some development and therefore implication for our industry.

The main points around this are:

  • The Compliance Guide will be scrapped and minimum performance aspects of it will be moved into Approved Documents
    • Industry will be left to provide additional guidance
    • Government will be adding BS7593 to the Approved Document

The details

BS7593, as a standalone document, does remain as advisory action; a code of practice, to give its official title. However, the integration of BS7593 into Part L effectively upgrades the status of BS7593, from an advisory action to a mandatory one.

So what does that mean for me?

In terms of every day changes related to the above, we have highlighted the top 5 here:

  • Installation of in-line filters to protect system components
    • A filter now needs to be installed, complementing a chemical clean and flush
  • Annual checks for concentration of chemicals and water cleanliness
    • Keep on top of inhibitor levels! 
  • Inhibitor should be re-dosed at 5 year intervals 
    • Whilst our X100 will give lifetime protection, a system should be cleaned, fully drained and refreshed every 5 years, adding new inhibitor
  • Biocidal and frost protection should be used where applicable
    • Across low temperature installations, keep fungal growth at bay using biocides and for systems liable to freezing, use inhibited antifreeze
  • Only 3 recommended cleaning methodologies: powerflushing, mains pressure and gravity cleaning
    • Ensure your clean is compliant, especially on powerflushes. An ‘external pump and tank arrangement’ is required

The Sentinel solutions

How can Sentinel help with the changes? This table below shows which of our product range fits into each part of the updated recommendations.

In-line filter





Biocide and frost protection


The timeframe

As is normally the case with these type of updates, a transition period is included. The first phase is a 2021 'uplift', with a view to the next fully updated version of the Regulations, called the ‘Future Homes Standard’, due to be implemented in in 2025

The other points

Also included in the updated Regulations are some other points, which focus on energy – notably targets and savings:

  • From 2025 new homes will not use fossil fuels and will not need retrofitting to become zero-carbon
  • Local Authorities will (for now) still be able to set their own local energy efficiency standards 
  • The 2021 uplift will mean 31% lower CO2 emissions than the current specification
    • Though the flexibility on how to meet the building target will be retained, Government expects heat pumps to be the primary heating technology for new homes
  • A carbon target will be retained alongside primary energy, fabric efficiency and product efficiency standards
  • Consultation proposals that new heating systems should be designed with flow temp of 55°C or lower (defining low temperature as 50°C or lower) is maintained
  • The Approved Document will require self-regulating control devices for heating systems but adds some examples where these will not be technically or economically feasible
  • Proposals to improve compliance will be taken forward as planned

The second update relates to new and existing non-domestic buildings. The main points here are:

For non-domestic buildings:

  • There will be an interim uplift for 2021 (27% lower emissions compared to the existing standard), and a Future Buildings Standard implemented in 2025 with more stringent requirements
  • Work preparing for 2025 will categorise different types of non-domestic buildings. Industry will be engaged in advance of the new Regs
  • For the 2021 version targets for primary energy, carbon and building services
  • Changes to Part F for non-dom and measures to reduce infection from aerosols

For existing buildings:

  • Requirement to fit a Service Reference Document when replacing a heating appliance

The review

So, in summary, the main point to be taken away is that BS7593 is now integrated into the Building Regulations. That elevates its status to beyond advisory and its points are now manadatory.

Have questions or want some advice? Call us on 01928 704 330 or drop us a line at with your questions, so we can answer them for you.