Key considerations when specifying smoke vents


Mark Baird from Bilco UK discusses how NSHEVs can be utilised to ensure the highest standards of safety for social housing and the key considerations that should be addressed to ensure successful specification

Natural Smoke and Heat Exhaust Ventilators (NSHEVs), more commonly known as smoke vents, provide essential ventilation in the event of a building fire. Installed in the roof, they open by sensors or remote control in response to exhaust smoke and noxious fumes.

Suitable for installation throughout social housing properties, the aim of a smoke vent is to make a dangerous situation safer for all individuals.

Dangers of smoke inhalation

While many may presume that the biggest danger of a fire are the flames, smoke inhalation can be far more dangerous and life threatening. Statistics from the UK Fire and Rescue Services stated that the most common cause of death for fire-related fatalities between April 2020 and March 2021 was being overcome by gas or smoke.

As a fire develops inside a building, it burns the oxygen in the air, removing most of the available oxygen as part of ‘incomplete combustion’, which in turn produces toxic and potentially deadly carbon monoxide.

When a fire ignites in an enclosed space the smoke rising from the fire gets trapped by the ceiling. It then begins to spread, forming an expanding layer that leaks into any gaps in the floors or walls. This can lead to individuals becoming disorientated, with their vision becoming increasingly clouded, hindering safe evacuation.

The installation of smoke vents in appropriate locations will protect occupants in the event of a fire by preventing the excessive build-up of smoke and noxious fumes. This subsequently reduces the risk of smoke inhalation, horizontal fire spread and secondary ignitions as the smoke is quickly exhausted, enabling fire-fighters to safely enter the building to tackle the blaze and building occupants to exit quickly.

Compliance check list

As a social housing provider, ensuring the right product is used in the correct context is paramount to not only ensuring it is fit for purpose, but is also compliant with relevant regulations and provides the highest levels of safety.

When specifying a smoke vent for a roof, it should be compliant with the Construction Products Regulation 305/2011, CE-marked with a Declaration of Conformity. It should also be manufactured to meet the demands of Building Regulations, Approved Document B, BS9999 and BS EN12101-2.

Choosing a smoke vent that meets all of these legislations will help to not only achieve compliance, but ensure the operational reliability and performance of the smoke vent throughout its lifetime.

The control of the smoke vent should also be considered, whether this is in the form of a dedicated management system or a solution integrated into a wider networked fire alarm system.

Aesthetic considerations

While the functionality and quality of the smoke vent will be the primary consideration, aesthetics can also be an important factor. Here a ‘one size fits all approach’ shouldn’t be applied as there are a wide range of elements to choose from to ensure the product is tailored to meet the project’s unique needs. Customisation may include elements such as hardware, paint finishes, curb liners, manual or automatic control units, open-close switches and rain and wind sensors.

While a NSHEV plays a pivotal role in fire protection by successfully exhausting smoke, for projects that require infrequent personnel access to the roof for maintenance, it is worth considering a smoke vent that can also be utilised as a roof access hatch.

By installing the smoke vent with the addition of a fixed vertical safety ladder, it can provide an adequate means of escape from the roof and offer access to contractors for infrequent maintenance.

Other considerations

Combining these functions into a single application, social housing providers also have the opportunity to take the proficiency of the installation even further, by choosing solutions that also act as a rooflight. This is particularly beneficial for social housing applications, where the installation provides the opportunity for natural light to enter the interior space, including corridors and stairwells.

This eliminates the requirements for multiple roof penetration, which can impact the overall thermal performance of the structure, as a significant proportion of heat is typically lost through the roof.

When specifying smoke vents for social housing applications, taking an alternative approach to specification that minimises roof penetrations, while addressing the individual requirements of each application, will ensure the solution is not only fit for purpose, but compliant with all relevant legislation.

Mark Baird is sales operations manager at Bilco UK