22 Mar, 2024

"No worse than existing" - a phrase that all designers, fire engineers and building control officers will be acutely familiar with.

But what does it mean?

Proposals to modify buildings without implementing necessary safety measures required in a new building, under the pretext that the building will not be worse than existing, should be carefully evaluated.

Changes triggering height or volume thresholds must be thoroughly considered, as the standard should, in principle, apply to the entire risk area.

This report delves into the perceived exploitation of a common fire safety argument: the existing condition and highlights the essential query: "Is it genuinely not worse than the existing condition?"

The author, through their professional capacity, has observed a trend wherein buildings undergo substantial alterations in occupancy and physical structure, such as increased building height or footprint. However, consideration of certain fire safety provisions is often omitted on the questionable basis that the altered design does not "worsen" the existing condition.

This argument stems from clauses outlined in Paragraph (3) of Regulation 4 of the Building Regulations 2010 and another clause in Approved Document B (ADB). It stipulates that for work on an existing building not compliant with applicable Building Regulations:

The work itself must comply with the applicable requirements of the Building Regulations.

The building must not be more unsatisfactory concerning the requirements than before the work was carried out.

Instances of this practice in recent years include extending residential buildings with additional storeys and expanding the building footprint with more apartments per floor. In such cases, if designed under contemporary guidance, fire safety provisions like suppression systems, firefighting shafts and lifts, automatic smoke control within corridors or lobbies, among others, would be expected, depending on the building height. However, the authors have observed situations where the fire strategy for altered buildings overlooks including certain fire safety provisions, arguing their absence in the existing building. Variations of this scenario include building extensions incorporating expected provisions while leaving the existing building portion largely or entirely unaltered.

Some of these designs receive Building Regulations approval and are constructed and occupied. While it may be assumed that such practices are rectified during quality assurance procedures and third-party reviews, it has been noted from anecdotal experience that some of these designs gain approval and proceed with limited concerns highlighted by authorities during the approval process.

It is however acknowledged the practical complexities of altering existing buildings, especially regarding retrofitting fire safety systems. However, they contend that the argument of "no worse than existing" is often exploited negligently to facilitate inadequate design. Examples provided, such as adding more storeys or apartments per floor, have the potential to significantly alter a building's risk profile. The increased number of apartments heightens the likelihood of a fire and the number of occupants, thus raising fire hazard risks without appropriate collective fire safety measures. Such alterations could also affect firefighting operations, adding pressure on fire services during firefighting and rescue operations within the building.

In light of these considerations, it is argued that unless the existing building and new alterations are demonstrably independent, i.e., the 'existing' portions do not interact with the 'new' portions, it cannot be reasonably argued that alterations do not worsen the existing condition. However, such independence is rarely the case, as existing buildings and extensions typically form a holistic system with many interacting components. Under these circumstances, it is challenging to assert that the existing condition is not worsened, and omitting provisions expected under contemporary guidance is reasonable only if clear evidence demonstrates the design collectively achieves an adequate level of safety, e.g., through a quantitative assessment considering both existing and new building portions.

It can be suggested that individuals within the fire safety industry propose revisiting or entirely abandoning the argument of "no worse than existing," advocating for improved safety of existing buildings during refurbishment or extension opportunities. However, they acknowledge potential complications and unforeseen consequences if implementation is not carefully considered. Nevertheless, before the industry can contemplate such changes, a minority of engineers must first be convinced that "no worse than existing" is not a loophole for exploitation or a means of sidestepping challenging discussions or avoiding responsibility for demonstrating adequate design.

Instances, where a fire safety measure is omitted with 'non-worsening' cited as the reason by the designer, engineer, or building control body, are recurring experiences.

Part of the rationale behind this clause is that building regulations are not retrospective. Engineers do not revisit every building to conduct upgrades whenever regulations change, ensuring occupants are not compelled to upgrade everything about their existing buildings with every work occurrence; for instance, replacing windows shouldn't necessarily mandate adding structural components.

However, the clause's misuse arises when it's decided that things are not 'worse'. The new works must fully comply, yet some may interpret this as meaning the new works can't be worse than the existing ones, which is evidently not the case.

Furthermore, it's less clear when the work has a less direct impact on the existing premises. For example, when adding floors to a building to an extent that changes classes (disproportionate collapse), serious consideration should be given to whether the whole building should meet current standards because the existing building supports the extension. Essentially, alterations changing the fire risk profile affect the entire building.

Another common issue arises when a vertical extension triggers the need for sprinklers due to increased height, which now reaches the threshold for a suppression system. In such cases, in principle, the whole building needs upgrading. Regarding guidance, BS 9251 (domestic sprinklers) states that when installing sprinklers, 'all parts of the premises should be sprinklered.' This ensures that fire protection for occupants of new accommodation is as provided for a new building under the approved document.

The non-worsening clause is also commonly cited when designers assess access and water supplies for the Fire and Rescue Service (FRS), with existing conditions typically accepted as adequate.

The practical challenges of achieving a holistic solution are often cited as reasons for inaction and should be evaluated case by case. However, some projects should not proceed if it's not feasible, and hence unsafe, to complete them properly.

While the FRS has limited options under the Regulatory Reform (Fire Safety) Order (FSO) to enforce Building Regulations retrospectively, it does expect continuous improvement and adaptation to new technologies. However, this is limited concerning a risk-based life safety assessment.

Finally, the opinion that this approach should be entirely abandoned is subject to debate. Any change in law can have unintended consequences, particularly for those undertaking minor works. Until this debate is resolved, better enforcement of building regulations across all building types is imperative. Therefore, any further clarification or guidance (by the Government) on how this regulation should be interpreted, given its open-to-interpretation nature recognised as the crux of the issue, would be most welcome.