Fire hydrants in industrial developments: how early planning reduces cost and design risk

Fire safety extends beyond sprinklers and alarm systems; hydrant provision can directly impact cost, programme, and compliance. For industrial developments, the overlooked detail of fire hydrant provision can derail project budgets and timescales. It sounds simple, but that is until you discover there’s conflicting guidance within the UK standards, along with differing interpretations and requirements from local fire authorities. The result? Risk in design that often surfaces too late, adding significant unplanned costs, often requiring additional infrastructure such as tanks, pumps, or upgraded water connections.

Why is it complicated?

Put simply, there is no ‘one size fits all’ approach as all sites are different. The size, capacity and location of existing water supplies need to be considered. Local water authorities often cannot guarantee the required flow rates which relevant industry guidance documents recommend for hydrant systems, based on the size of the site. Some recommendations can be in excess of 75 litres per second for large-scale sites, which is rarely achievable through a standard mains water connection without network upgrades or supplementary storage.

Fragmented guidance in BS 9990, paired with differing local fire authority requirements and the need for building control approval, leaves room for interpretation and means that fire engineers must design what is best for individual sites rather than approach it as a tick-box exercise.

Compliance vs Practicality

Fire hydrant provision often exposes a gap between regulatory compliance and what can realistically be delivered on site.

Whilst there are varying degrees of guidance within the UK, Building Regulations Approved Document Part B: Volume 2 states that where no piped water supplies are available, or where the pressure and flow rates in the water main are insufficient, an alternative source of water supply should be provided. The solution to this could be in the form of a static water tank with a minimum capacity of 45,000 litres, or by utilising a nearby natural water source such as a river, canal or pond.

The guidance does not define what constitutes ‘insufficient’ pressure or flow, leaving interpretation open to building control and fire authorities. Generally, a flow rate of 25 litres per second may be considered appropriate, but again, this is dependent on which guidance document is being referred to and whether the local fire authority and building control accept this.

Conflicting requirements often lead designers to adopt overly conservative solutions, which can add unnecessary costs to the project. An example of this is the requirement for available stored water within a hydrant system tank and the use of dual pumps (one electric and one diesel), which adds significant costs to a scheme.

Industry shift

Historically, developers have relied on a simple mains water provision delivering a flow rate of around 8 litres per second to service industrial units for hydrant use. This was due to the flexible interpretation of the guidance and light enforcement. This approach is no longer accepted. 

The Grenfell tragedy and subsequent legislation changes have heightened awareness of fire safety across all sectors. Whilst much focus has been on the residential sector, industrial developments are now under similar pressure to demonstrate robust fire strategies.

Building control and fire authorities are taking a stricter role too. They expect clear evidence that hydrant provisions are sufficient for the site. This is then also expected by insurers. 

How to de-risk a project

There are some clear steps that fire engineers can assist with to reduce uncertainty, risk and to avoid unnecessary project costs. 

Developers need to engage with fire consultants early. Waiting until Stage 4 (post-tender) is often too late. By bringing them on board at the concept stage, they can ensure a strategy is appropriately planned and liaise with the relevant authorities at the earliest opportunity. 

Fire consultants will be able to identify water access to the site, including the distance to any existing public hydrants, and can advise on the risk to the building due to intended use. 

They can consult with the local water authority to establish the available mains water pressure and flow rates and then discuss these with the local fire authority to establish compliance with their minimum requirements. This will allow the team to specify what the project specifically needs, rather than working to a design that is assumed based on worst-case guidance recommendations.

Hydrant provision is a critical design constraint. Early engagement with fire engineers reduces uncertainty, controls cost and avoids late-stage redesign.