Do Fire Tanks Need Relining? Signs and Decisions

A sprinkler tank can look serviceable from the outside while deterioration is developing below the waterline. That is why the question, do fire tanks need relining, cannot be answered by age alone. Relining is often the most effective way to restore a deteriorating fire water storage tank, but it must follow a proper assessment of the tank’s structure, existing coating or liner, roof condition and ability to continue providing dependable water to the sprinkler system.

For facilities managers, building owners and responsible persons, the priority is clear: the tank must remain watertight, structurally sound and available when the fire protection system calls upon it. A planned relining project can extend the serviceable life of an ageing asset at substantially lower cost and disruption than complete replacement. Equally, applying a new liner to a tank with unresolved structural defects is not a sound engineering solution.

Do Fire Tanks Need Relining?

Not every fire tank needs relining, but many older sectional steel, galvanised steel and concrete tanks will require it at some point in their operational life. The decision should be based on condition, not assumption.

A liner is the primary water-retaining barrier in many sprinkler tanks. Over time, this barrier can harden, crack, lose elasticity, split at seams, deteriorate around penetrations or become damaged by abrasion and maintenance activity. If water reaches the tank structure, corrosion can accelerate. In steel tanks, that may lead to reduced plate thickness, degraded fixings, leaks and more extensive refurbishment requirements.

Relining is normally considered where the existing liner has reached the end of its effective service life but the tank shell remains suitable for continued use. A correctly specified EPDM lining system can provide a durable, flexible water-retaining membrane and protect the tank structure from further internal exposure. It can also be combined with repairs to flanges, bolts, joints, roof components and access arrangements where these are required.

The key point is that a liner does not make a weakened tank structurally safe. It protects a serviceable structure and restores containment. An experienced survey distinguishes between a tank that is a good candidate for refurbishment and one that needs significant structural remediation or replacement.

Signs That a Sprinkler Tank May Need Relining

Visible leaks are an obvious warning sign, but they are not the only one. A tank can lose water slowly through failed seams or concealed liner defects without producing dramatic external evidence. Changes in water level, unexplained pump house alarms, dampness around the tank perimeter and repeated topping-up should all be investigated promptly.

During inspection, particular attention should be given to the liner at corners, floor-to-wall transitions, panel joints, bolt heads, pipe penetrations, suction connections and overflow arrangements. These locations experience movement, stress or abrasion and are common points of failure. A liner that has become brittle, creased, detached or visibly split should not be left until a leak develops.

The following conditions commonly indicate that relining or more detailed investigation is required:

• Cracks, tears, pinholes, worn areas or open seams in the existing liner.

• Water loss, staining, corrosion marks or moisture around external panel joints.

• Corrosion to internal steelwork, bolts, washers, supports or tank base details.

• A liner approaching or exceeding its expected service life, particularly where condition records are limited.

• Previous patch repairs that are becoming frequent or are no longer addressing the underlying cause.

A roof in poor condition also changes the risk profile. Failed roof sheets, corroded purlins, damaged access hatches and ineffective weather protection can introduce contamination, increase internal corrosion and create unsafe access conditions. In these cases, relining may form part of a wider sprinkler tank refurbishment rather than being the whole scope of works.

Inspection Before Any Relining Decision

The right starting point is a technical condition survey. This should establish the actual condition of the tank rather than relying on a visual check from the roof or external elevations.

Traditionally, inspecting a tank internally could mean draining it, isolating the fire protection supply and arranging compensatory measures. That can be costly and operationally difficult, particularly at warehouses, manufacturing sites and premises with insurer requirements. Remotely operated vehicle, or ROV, inspection offers a practical alternative for many tanks. It allows a specialist to assess internal areas below the waterline without draining the tank, reducing disruption while producing useful visual evidence of liner condition, sediment, corrosion and defects.

A survey should also examine the external structure. Tank panels, staves, base arrangements, tie rods, roof supports, handrails, ladders and low-level access housing all contribute to safe and reliable operation. The surveyor should identify whether any observed corrosion is superficial, whether it requires local repair, or whether it affects the tank’s structural integrity.

For sprinkler water storage, decisions must be made with the wider system in mind. The required capacity, water level arrangements, pump suction performance and applicable design standard must not be compromised by the refurbishment method. Where the tank supports a sprinkler installation designed to BS EN 12845, LPC Rules or another specified standard, the project scope should be reviewed against the relevant requirements and insurer expectations.

When Relining Is the Most Sensible Option

Relining is generally a strong commercial and technical option when the tank structure is fundamentally sound, the existing membrane has failed or aged, and repairs can be completed without disproportionate intervention. It is particularly valuable where a replacement tank would involve major enabling works, restricted site access, crane operations, lengthy downtime or changes to connected pipework and foundations.

The process usually involves carefully planned isolation, controlled draining where necessary, cleaning and preparation of the tank interior, targeted repairs, installation of the replacement liner and final checks before return to service. The exact programme depends on tank size, access, the condition found, water storage arrangements and the resilience measures available on site.

An EPDM liner is often selected because it remains flexible and accommodates movement within sectional tanks. It can be a practical solution for tanks with numerous joints and varying internal details. However, material selection should not be automatic. The liner specification must suit the tank construction, water conditions, operating temperature range and detailing around penetrations and fittings.

A well-managed refurbishment can also address issues that cause future maintenance problems. Replacing deteriorated roof and purlin components, improving access, repairing fibreglass sections or renewing corroded fittings during the same project can avoid repeated interventions and provide a clearer maintenance baseline.

When Relining May Not Be Enough

There are circumstances where relining alone is not appropriate. Significant loss of steel thickness, distorted panels, extensive corrosion beneath flanges, failed foundations, compromised supports or serious roof instability may mean that structural repairs are required first. In more severe cases, complete tank replacement may offer the safer and more economical long-term outcome.

It is also necessary to identify why the original liner failed. A replacement liner installed over sharp corrosion products, poorly repaired fixings or unresolved movement will be vulnerable to early damage. The preparation and repair work behind the liner is as important as the membrane itself.

Cost should be assessed over the asset’s remaining life, not simply against the immediate price of a new liner. A focused refurbishment can defer major capital expenditure and preserve a proven tank structure. However, if repeated repairs are likely, the structure has materially deteriorated or the tank no longer meets operational requirements, replacement may provide better value and reduce risk.

Planning the Work Around Fire Protection Availability

Because a sprinkler tank is safety-critical, relining cannot be treated like a routine maintenance task. The works need a clear method statement, programme, isolation plan and communication process involving the site, fire protection contractor, insurer and any relevant stakeholders.

Before work starts, establish how impairment will be managed, whether temporary fire safety measures are required and who has authority to return the system to normal operation. Following completion, the tank should be checked for water retention, liner fit, correct reinstatement of connections and any defects that could affect the sprinkler water supply.

Nationwide Water Solutions Ltd approaches sprinkler tank relining as part of a full asset condition solution, combining inspection, repair, refurbishment and replacement capability where required. This helps ensure the recommendation reflects the tank’s actual condition rather than a one-size-fits-all service.

A fire tank does not need relining simply because it is old. It needs the right intervention at the right time, based on evidence. A specialist survey gives responsible persons the information to protect sprinkler availability, control lifecycle costs and act before a manageable defect becomes an emergency.