Low-pressure water mist
In social housing developments operated by housing associations, tenant and resident safety is of paramount importance.
In the years following Grenfell, regulations around fire suppression have undergone extensive review. Fire protection is no longer simply about specifying the right equipment. It increasingly involves competence, design responsibility, documentation, commissioning, maintenance and demonstrating performance.
For social housing, more weight is added to this responsibility when considering vulnerable or specialised residents: Supported housing, sheltered accommodation and properties housing elderly or mobility-impaired tenants require systems that can suppress fires quickly without relying on immediate manual evacuation.
For architects, specifiers and installers, this presents a regulatory obligation to provide the correct fire suppression to protect tenants and residents according to Approved Document B.
Since 2020, it has recommended sprinklers in new social housing blocks over 11m. This means water mist fire suppression systems – which fall under the category of sprinklers – are a viable fire suppression option for a large proportion of new residential development, including many social-housing schemes.
iCO was the first to release a high-pressure nozzle successfully tested to the new standard, followed by a low-pressure nozzle that recently passed stringent independent fire testing to prove fire suppression capability for residential buildings.
Water mist fire suppression systems tackle fire by delivering a fine spray of water directly into the affected area. The system produces droplets small enough to penetrate the fire, where they rapidly absorb heat and turn into steam. This removes heat from the flames and surrounding gases, helping to cool the fire and reduce the conditions needed for combustion to continue.
The effectiveness of water mist comes largely from the size of its droplets. Compared with conventional sprinkler systems, the much smaller droplets provide a significantly greater surface area relative to their volume. This enables them to absorb heat and evaporate rapidly, helping to control fire growth, limit temperatures and reduce the spread of hot smoke and gases. A low-pressure water mist system operates at approximately 20-35 L/min, while a traditional sprinkler system can use twice this amount or more.
As well as cooling the fire, the rapid conversion of water into steam can displace oxygen locally, further restricting combustion.
Water mist also comes with benefits in terms of ease of retrofit. Older social housing stock often has space constraints or lacks infrastructure for large water storage tanks. Water mist installation often avoids major structural changes.
This is particularly relevant in a building that wasn’t originally designed with automatic fire suppression, sprinklers, but a change of use, refurbishment or wider fire-safety assessment may identify a need for additional protection.
That potentially creates issues around:
For a retrofit, water mist can be a good option where conventional sprinkler infrastructure is difficult to accommodate, particularly where reducing pipe sizes and water storage requirements is important. The system still needs to be appropriately designed, tested and specified against the relevant standard and the building’s fire strategy.
Water Damage and Drainage: Traditional high-flow sprinklers can cause extensive water damage to adjacent properties or tenant belongings. Low-water alternatives like high-pressure water mist limit collateral damage while controlling the fire.
A single sprinkler head typically discharges around 55 litres of water per minute when activated. Category 2 & 3 (Flats under 18m, Care Homes, HMOs): Minimum 30 minutes of water supply duration that makes a total of 1650 litres required per sprinkler nozzle.
The iCO water mist nozzle is among the most discreet available, sitting just 6mm below the ceiling line. In standby mode, the head is fully recessed into the ceiling and concealed behind a small cover, keeping it virtually invisible.
When activated, the head automatically deploys from the ceiling and immediately begins discharging a fine water mist to suppress heat and flames. This discreet design not only maintains the clean, uncluttered appearance of the ceiling but also helps protect the nozzle from accidental damage or tampering that could lead to unwanted activation.
A low-pressure water mist system can potentially address some of the physical and installation problems associated with conventional sprinklers for mandatory fire suppression.
| Issue | Conventional sprinkler | Low-pressure water mist |
| Water consumption | Relatively high | Much lower |
| Pipework | Larger | Smaller |
| Ceiling void | Can be demanding | Easier |
| Tank requirements | May be substantial | Smaller |
| Pumping equipment | Can be substantial | Smaller |
| Retrofit | Can be disruptive | Less intrusive |
| Water damage | Can be significant | Reduced |
| Architectural impact | More visible pipework | Less intrusive |
In England, regulations dictate that automatic sprinklers or compliant water mist systems are required when you reach certain thresholds. Scotland demands automatic fire suppression across a much wider range of residential buildings, including:
In Wales, automatic suppression is required in specified residential circumstances, within a separate Welsh regulatory framework.
Find out more about iCO low-pressure water mist systems – and how you can compliantly specify and install them in housing association developments.
