This article explains the reasons why a corrigendum may be issued and summarises the content of the corrigendum.
Debbie Shields | Communications Manager
This article explains the reasons why a corrigendum may be issued and summarises the content of the corrigendum, focusing in particular on the changes being made to provisions in BS 7671 relating to fire detection and fire alarm systems and what this means for electrical contractors.
Clause 6.2.1 also states that: Errors inadvertently introduced during the drafting or production of a standard that could lead to incorrect or unsafe application of the standard can be rectified by publication of a corrigendum.
Clause 6.2.2 of BS 0 states that where corrigenda are published, additions, changes and deletions are marked with corrigendum tags. It further clarifies that issue of corrigenda does not change the publication date of a standard, but a reference to the corrigendum is included in the standard's title.
(i) serious injury to, or loss of, human life
(ii) failure of a safety service, as defined in Part2
(iii) significant financial or data loss.
In the time since AMD2 was published it became apparent that the reference to 'safety service, as defined in Part 2' was problematic.
Safety service is defined in Part 2 of BS7671as:
'An electrical system for electrical equipment provided to protect or warn persons in the event of a hazard, or essential to their evacuation from a location.'
The general consensus is that a fire detection and fire alarm system in accordance with the BS 5839 series is deemed to be a safety service when referencing this definition. However, and after close examination of these standards and those for the component parts of such systems, it can be seen that supplemental protective overvoltage control is not necessary.
The problem introduced by indent ii) of Regulation 443.4.1
Focusing on the provision of-fire detection and fire alarm systems in domestic premises, the installation of Grade D fire detection and fire alarm systems in existing dwellings is not required unless legislation relating to their intended means of occupation requires such.
Nevertheless, as is made clear in BS 5839-6, the installation of such systems in existing dwellings is to be encouraged. Clauses 9.1 and 15.1 of that standard extol the benefits of providing a Grade D system in new dwellings. It is logical therefore to suggest that the installation of Grade D systems in existing dwellings is preferable to Grade F systems, which do not have a mains supply and rely solely on batteries as their source of supply.
Where a Grade D system is to be installed in an existing premises, a supply would need to be provided from either a dedicated final circuit or from an existing lighting circuit (Clause 15.4 a) of BS 5839-6). These additions to the electrical installation have to comply with the requirements of the version of BS 7671 current at the time the work is carried out (see indent c) of Clause 16.4 of BS 5839-6).
BS 7671 applies to new work and to additions or alterations to an existing installation (see Introduction to Amendment 2:2022 and Regulation 110.1.2). As a result, a supply to a Grade D system, by either means described in Clause 15.4 a) of BS 5839-6, may only be provided if all relevant requirements of BS 7671 are met.
'You're around eight times more likely to die in a fire if you do not have a working smoke alarm in your home.’
Source: Home Office guidance on fire safety in the home
Because of the introduction in AMD2 of indent ii) in Regulation 443.4.1, this required additionally the provision of protection against transient overvoltages as the majority of existing installations in domestic premises would not have such protection already.
Installation of such overvoltage protection will inevitably add to the cost of the installation of the Grade D system, both in terms of materials, time and labour costs to install. It is hard to quantify accurately to what extent the cost of installation would be increased, as this will depend on factors such as:
In short, what was previously a very straightforward installation becomes significantly more complex.
However, it is clear that the requirement to provide transient overvoltage protection before a supply can be given for a Grade D fire detection and fire alarm system has discouraged some local authorities, housing associations and property owners from installing such systems where no alarm system was present previously, or from upgrading the existing Grade F systems to Grade D. As a result, vital improvements to the safety of the occupants of the premises, and indeed of those in adjoining properties, have not been made in some cases despite such works having been planned for ahead of the publication of AMD2.
After much consideration of the related standards for products used in fire detection and fire alarm systems (BS 5446 series; BS EN 54 series); protection against lightning (BS EN 62305 series); and electromagnetic compatibility (BS EN 50130-4; BS EN 61000-4 series), it was agreed to delete:
However premises, or parts thereof, containing a fire detection and fire alarm system may require protection against transient overvoltages due to:
This article summarises the changes made in the corrigendum in respect of Sections 443 and 534, the reasons for these changes and what they mean when installing fire detection and fire alarm systems.
Certsure welcomes the clarification provided in respect of fire detection and fire alarm systems and the requirements for protection against transient overvoltages.
What is a corrigendum?
BS 7671, like all other British standards, is drafted in accordance with BS 0:2021 A standard for standards - Principles of standardization. Clause 6.2.1 lays out the principles for maintenance of a British standard. It states that, while all such standards are subject to review every five years, if evidence is provided that a standard or part thereof is unclear, inaccurate, disputable or in any other way unfit for purpose, steps will be taken to rectify the problem(s). It further advises that any such steps will be proportionate to the severity of risk posed, with urgent safety problems expected to receive urgent attention while trivial errors may be left uncorrected until the need for a more substantial amendment of the standard arises.Clause 6.2.1 also states that: Errors inadvertently introduced during the drafting or production of a standard that could lead to incorrect or unsafe application of the standard can be rectified by publication of a corrigendum.
Clause 6.2.2 of BS 0 states that where corrigenda are published, additions, changes and deletions are marked with corrigendum tags. It further clarifies that issue of corrigenda does not change the publication date of a standard, but a reference to the corrigendum is included in the standard's title.
What is in Corrigendum 2023 to BS 7671: 2018+A2:2022?
The corrigendum consists of amendments to the following five sections within BS7671:- 422 Precautions where particular risks of fire exist
- 443 Protection against transient over voltages of atmospheric origin or due to switching
- 534 Devices for protection against overvoltage
- 701 Locations containing a bath or shower
- 710 Medical locations
Section 443
During the development of Amendment No 2 to BS 7671:2018 (AMD2), a decision was made to remove the risk assessment procedure to determine whether protection against overvoltage was required. Instead, AMD2 contained separate requirements relating to overvoltages due to the effects of indirect lightning strokes (443.4.1) and transient overvoltages caused by equipment (443.4.2). Regulation 443.4.1 stated that overvoltage protection was required where the consequences caused by the overvoltage could result in:(i) serious injury to, or loss of, human life
(ii) failure of a safety service, as defined in Part2
(iii) significant financial or data loss.
In the time since AMD2 was published it became apparent that the reference to 'safety service, as defined in Part 2' was problematic.
Safety service is defined in Part 2 of BS7671as:
'An electrical system for electrical equipment provided to protect or warn persons in the event of a hazard, or essential to their evacuation from a location.'
The general consensus is that a fire detection and fire alarm system in accordance with the BS 5839 series is deemed to be a safety service when referencing this definition. However, and after close examination of these standards and those for the component parts of such systems, it can be seen that supplemental protective overvoltage control is not necessary.
The problem introduced by indent ii) of Regulation 443.4.1
Focusing on the provision of-fire detection and fire alarm systems in domestic premises, the installation of Grade D fire detection and fire alarm systems in existing dwellings is not required unless legislation relating to their intended means of occupation requires such.
Nevertheless, as is made clear in BS 5839-6, the installation of such systems in existing dwellings is to be encouraged. Clauses 9.1 and 15.1 of that standard extol the benefits of providing a Grade D system in new dwellings. It is logical therefore to suggest that the installation of Grade D systems in existing dwellings is preferable to Grade F systems, which do not have a mains supply and rely solely on batteries as their source of supply.
Where a Grade D system is to be installed in an existing premises, a supply would need to be provided from either a dedicated final circuit or from an existing lighting circuit (Clause 15.4 a) of BS 5839-6). These additions to the electrical installation have to comply with the requirements of the version of BS 7671 current at the time the work is carried out (see indent c) of Clause 16.4 of BS 5839-6).
BS 7671 applies to new work and to additions or alterations to an existing installation (see Introduction to Amendment 2:2022 and Regulation 110.1.2). As a result, a supply to a Grade D system, by either means described in Clause 15.4 a) of BS 5839-6, may only be provided if all relevant requirements of BS 7671 are met.
'You're around eight times more likely to die in a fire if you do not have a working smoke alarm in your home.’
Source: Home Office guidance on fire safety in the home
Because of the introduction in AMD2 of indent ii) in Regulation 443.4.1, this required additionally the provision of protection against transient overvoltages as the majority of existing installations in domestic premises would not have such protection already.
Installation of such overvoltage protection will inevitably add to the cost of the installation of the Grade D system, both in terms of materials, time and labour costs to install. It is hard to quantify accurately to what extent the cost of installation would be increased, as this will depend on factors such as:
- Are suitable devices available for retrofitting into existing consumer units/distribution boards, taking into account the suitability/compatibility requirements of regulation 536.4.203.
- Is there sufficient space to install an additional enclosure to house the required overvoltage protection alongside the existing consumer unit.
- Will it be necessary to install a new consumer unit in order to provide the overvoltage protection.
In short, what was previously a very straightforward installation becomes significantly more complex.
The implications for the safety of persons
It is important that a requirement in BS 7671 should not in any way discourage someone from having a fire detection and fire alarm system installed.However, it is clear that the requirement to provide transient overvoltage protection before a supply can be given for a Grade D fire detection and fire alarm system has discouraged some local authorities, housing associations and property owners from installing such systems where no alarm system was present previously, or from upgrading the existing Grade F systems to Grade D. As a result, vital improvements to the safety of the occupants of the premises, and indeed of those in adjoining properties, have not been made in some cases despite such works having been planned for ahead of the publication of AMD2.
The solution
As a result of concerns being raised in respect of the unintended consequences of the changes in Regulation 443.4.1 as described in this article, JPEL/64, the joint IET/BSI committee responsible for the maintenance of BS 7671, set up a working group to look into the issues being raised.After much consideration of the related standards for products used in fire detection and fire alarm systems (BS 5446 series; BS EN 54 series); protection against lightning (BS EN 62305 series); and electromagnetic compatibility (BS EN 50130-4; BS EN 61000-4 series), it was agreed to delete:
- indent (ii) of Regulation 443.4.1, and
- the text in Table 443.2 citing 'alarm panels, computers and home electronics' as examples of overvoltage category 1 equipment, and
- the text in the note to Regulation 534.4.1.1 giving 'fire/security alarm systems' as an example of sensitive and critical equipment.
Do fire detection and fire alarm systems require overvoltage protection?
The presence of a fire detection and fire alarm system designed and installed in accordance with the recommendations given in the BS 5839 series does not, of itself, require the provision of overvoltage protection as described in Sections 443 and 534 of BS 7671.However premises, or parts thereof, containing a fire detection and fire alarm system may require protection against transient overvoltages due to:
- direct lightning strikes; in which case, reference should be made to the BS EN 62305 series of standards for protection against lightning, or
- transient overvoltages due to either indirect lightning strokes or caused by equipment; in which case the relevant requirements of Regulation group 443.4 must be met.
Summary
On 15 May 2023, a corrigendum to BS 7671:2018+A2:2022 was published for immediate implementation. This contains corrections to matters covered in Sections 422, 443, 534, 701 and 710.This article summarises the changes made in the corrigendum in respect of Sections 443 and 534, the reasons for these changes and what they mean when installing fire detection and fire alarm systems.
Certsure welcomes the clarification provided in respect of fire detection and fire alarm systems and the requirements for protection against transient overvoltages.
