Your Guide to The Construction Products Regulation (CPR)
- European legislation affecting products used in fixed installations in buildings and construction
- Is an assessment on how cables react in the event of fire
- Provides a common language across Europe to aid purchasing decisions
- Assessed against European Standard EN 50575:2018
- In effect for electrical cables since 1st July 2017
- Will continue to apply to the UK after 1st January 2021
Importantly, CPR doesn’t override any other national or international standards or attempt to harmonise building codes. Each European country sets its own requirements over and above compliance.
- Doesn’t specify how or where a cable should be used
- Covers all electrical cables used internally in fixed installations with the exception of fire-resistant circuit integrity cables (‘fire performance cables’)
- It also affects power distribution cables primarily installed externally, including direct buried or in cable ducts, where terminated in panels inside a building
- Responsibility for CPR compliance is felt throughout the supply chain, but as it is based on installation location rather than product-specific the onus falls on designer and installer to confirm adherence.
In many cases, an additional assessment for the following criteria is also required:
The ‘Euroclassifications’ as they are properly known as, provide the common language for fire performance assessment. Cable Euroclasses have the suffix ‘ca’ to clearly identify the product type.
Cables classified Dca and above will also have 3 sub-classifications
- s1 – low levels of smoke density (an LSZH cable)
- s1a – LSZH over 80% light transmittance
- s1b – LSZH over 60% light transmittance
- s2 – Moderate levels of smoke density
- s3 – Emits dense smoke – neither s1 or s2
- d0 – no flaming droplets
- d1 – low levels of flaming droplets
- d2 – Flaming droplets – neither d0 or d1
- a1 – Low levels of acid gas emissions
- a2 – intermediate levels of acid gas emissions
- a3 – Acid gases - neither A1 nor A2
Whilst compliance is mandatory across Europe, countries have the right to set the minimum classifications that must be achieved for relevant installations inside their borders. Some are more stringent than others. Many have taken a risk assessment based approach, looking at the type of installation or taking fire suppression systems into account.
BS7671 Wiring Regulations requires compliance but does not stipulate a minimum classification. Best practice recommends a minimum Eca.
Additionally, BS6701 for data and telecoms cables offers ‘voluntary guidance’ relating to CPR. With reference to ‘installation cables’ it recommends a minimum classification of Eca. It recommends a minimum Cca where these installation cables are run over fire exits and fire escape routes. It defines installation cables as ‘cables intended for installation into pathways which are hidden (below floors, above ceilings, behind walls) or to which access is limited and which can either be terminated in-situ or “pre-terminated”.’
1ˢᵗ January 2021
The UK’s exit from Europe on 1ˢᵗ January 2021 did not remove the requirement for compliance with CPR.
CPR will continue to be mandatory for fixed wiring installations in buildings and construction, but using cables that have been assessed by a UK Approved Body. Assessment under EN 50575 (CPR) will move to become to a UK designated standard, but with parity of requirements. The common language for cable assessment will remain.
UKCA marking will replace CE marking, the European Economic Area (EEA) assessment mark. The UKCA mark will denote products assessed and approved for the UK market. Just as CE marking does not claim to be a European product, UKCA does not state that a product has been made in the UK, simply that it has been assessed and met the performance and safety criteria set out for sale.
There is a transition period during which the CE mark will remain valid. Only after 1ˢᵗ January 2023 will it be obligatory to also list the UKCA assessment mark if the cables are for use in the UK. In many cases, cables will be dual marked with CE and UKCA as installation location is not geographic specific.
CPR compliant cables will have certain documentation to support them:
- DoP – A Declaration of Performance. Based on the testing certificate, this attests to the performance criteria met and links to the testing body. It must be retained for 10 years from the date the cable was placed on the market.
- CE Mark – The European conformity assessment mark. Whilst it may be printed on the sheath legend it is not always mandatory however it must be on the label attached to the packaging. (this may be dual listed alongside UKCA in the coming months).
- CPR CE Labelling – to include key Marks of assessment, CPR Euroclasses, and the DoP reference number amongst other details. This labelling ties back to the above declarations.
- Technical documentation – Describes product, design and manufacturing techniques, Any deviation would require the cable to be resubmitted for a new assessment. As with the DoP this is maintained for 10 years.
As the installer, designer or end user it is not necessary to physically hold the DoP or technical documentation. Part of using a trusted supplier is the assurance that this documentation will be retained and made available in the event it is called upon.
The ‘Euroclassifications’ as they are properly known as, provide the common language for fire performance assessment. Cable Euroclasses have the suffix ‘ca’ to clearly identify the product type.
Cables classified Dca and above will also have 3 sub-classifications
- s1 – low levels of smoke density (an LSZH cable)
- s1a – LSZH over 80% light transmittance
- s1b – LSZH over 60% light transmittance
- s2 – Moderate levels of smoke density
- s3 – Emits dense smoke – neither s1 or s2
- d0 – no flaming droplets
- d1 – low levels of flaming droplets
- d2 – Flaming droplets – neither d0 or d1
- a1 – Low levels of acid gas emissions
- a2 – intermediate levels of acid gas emissions
- a3 – Acid gases - neither A1 nor A2
EN 60332-1-2 is a requirement for all classifications, with the exception of Class Aca. It defines the test of a single insulated cable or wire with a 1kW pre-mixed flame.
The cable is ignited for 1 minute before the flame is removed. The cable should self-extinguish. The length of burn should not exceed 425mm.
Meeting these requirements is sufficient for Euroclass Eca. Where it fails to meet the requirements it would be classified Fca.
To achieve a higher classification up to B1ca, the test must be performed on bunched cables with additional measurements for total heat release, peak heat release, and fire growth index recorded.
1. Smoke Density
EN 60134-2 is known as the 3 metre cube test and is used to determine the density of smoke emitted when burning. An S1 classification – whether s1a or s1b – denotes a low smoke cable (LSZH).
Performed inside a 3m x 3m x 3m chamber and lasting for a period of 40 minutes, the cables are burned whilst a beam of white light crosses the chamber. A fan is used to circulate the air, mimicking a fire scenario. The smoke density test monitors the transmittance of this light with a minimum 60% light visibility being required for LSZH cables.
Smoke density testing isn't usually conducted on PVC cables as when subjected to fire the cable sheathing and insulation materials emit large quantities of toxic fumes and light obscuring black smoke which would completely cloak the white light beam.
2. Fall of Flaming Droplets during combustion
Recording “the material separating from the specimen during the test and continuing to flame for a minimum period as described in [the] test method” is part of standard EN 50399. It is tracked throughout the 20 minute duration of the ladder rack vertical flame test and documents the number of droplets or particles that reach the floor of the test chamber.
To achieve the classification d0 no fall of droplets or flaming droplets are permitted.
3. Smoke Acidity
Acid gases such as Chlorine may be emitted from some of the insulation and sheathing materials when burnt. These can significantly hinder evacuation of a building and cause damage to sensitive equipment. Principal among these acid gases is chlorine which would combine with water, whether that be naturally present in the air, in someone’s eyes, nose and throat, or from fire suppression systems, to make hydrochloric acid.
LSZH cables – Low Smoke Zero Halogen - are defined as having a pH value no less than 4.3 and a conductivity not exceeding 10µS/mm – a requirement to meet the a1 sub-classification.
Tested to EN 60754-2, the test for Smoke Acidity is split into two – determining the Halogen Acid Gas content and separately determining the pH value of those gases. For the first part, samples are cured before being placed into a tube in a furnace and heated under a steady 20ml/mm²/h stream of dry air up to a temperature of 800ºC, and maintaining that temperature for a period of 20 minutes, with the gas samples collected and analysed. To determine the pH value, samples are again placed in a tube furnace, then heated for 30 mins at 935ºC. As the material heats, gases are emitted which are absorbed into a catch solution before the pH value and the conductivity of the solution is then be measured and recorded.
The testing requirements – the AVCP (Assessment and Verification of Constancy of Performance) – dictate what body can undertake testing for which Euroclassification, as well as the frequency that testing must be conducted.
- AVCP 1+ covers Class Aca, B1ca, B2ca and Cca - requires 2x annual testing and auditing by a Notified Body
- AVCP 3 covers Class Dca and Eca - requires annual testing by Notified Body or Notified Laboratory
- AVCP 4 covers Class F - requires annual testing, self-certified by the manufacturer
There are around 40 Notified Bodies (and 3 that will be designated to undertake UKCA CPR testing when it becomes mandatory). Manufacturers can submit cables to any Notified Body for independent testing – it’s not dependent on where the cables are to be sold. However, the manufacturer must state the Euroclass it wishes the cable to be tested against at the point of submission. If the cable fails to meet the required standards, it can only be classified as Eca or Fca without further testing.
