GRP ONE-PIECE WATER STORAGE TANKS
Tricel one-piece tanks are factory-manufactured GRP cold water storage tanks, built and moulded off site and delivered to the project as a single complete unit — for commercial, institutional and building-services applications where the finished tank can be transported into position and adequate site access is confirmed.
01
What Is a One-Piece GRP Water Storage Tank?
A one-piece GRP water storage tank is a cold water storage vessel moulded from glass-reinforced plastic (GRP) — a composite of glass fibre and resin — and manufactured as a single complete unit in the factory before delivery. Unlike a sectional (panel) tank, which arrives as flat-packed panels and is bolted together on site, a one-piece tank leaves the factory fully formed and is lifted, wheeled or craned directly into its final position as one item.
This construction method means there is no on-site panel assembly, sealing or bolting sequence to complete before the tank can be commissioned. The trade-off is that the whole tank — not individual panels — has to travel the full delivery route from the delivery vehicle to its final location, so the dimensions of doorways, corridors, stairwells, lift shafts and plant-room openings along that route matter as much as the space available once the tank is in place.
One-piece tanks are typically specified for cold water storage duties within the 45 L to 6,000 L range covered by the Tricel range — drinking (potable) water storage, general building-services (non-potable) storage, and break tanks or header tanks feeding a boosted or pressurised system downstream. Where a project’s required capacity sits above this range, or where the access route cannot accommodate a complete moulded unit, a sectional tank is normally the more practical choice, since individual panels can be carried through restricted openings and assembled in the plant room itself. Final product selection should always weigh required capacity, the physical access route, plant-room dimensions, the fittings and connections needed, ongoing maintenance access, and the specific project specification — it is rarely a decision on capacity alone.
GRP One Piece Tank - Key Parameters
Construction Method
Factory-manufactured, one-piece GRP tank
Material
Glass-Reinforced Plastic (GRP)
Capacity Range
45 L – 6,000 L
Water type
Insulated tanks across the range. Uninsulated tanks available in 10-gallon and 70-gallon sizes only for non-potable applications.
Insulation
25 mm insulation available. 50 mm insulation not supplied.
Drainage
Standard drainage arrangements. Fully self-draining options are not available.
Colour
Standard grey only.
Installation
Delivered as a complete unit where access permits
02
GRP One Piece Water Tank Specifications
Tricel’s standard one-piece water tank sizes run from 45 to 6,000 litres, manufactured in glass-reinforced plastic to a factory-built, one-piece design. The table below summarises the core specification for the standard one-piece cold water storage tank range.
Useful information for your enquiry
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Specification
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Details
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Construction method
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Factory-manufactured one-piece GRP construction
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Material
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Glass-reinforced plastic (GRP)
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Capacity range
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45 to 6,000 litres
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Delivery Format
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Complete, factory-assembled single unit
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Potable suitability
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Manufactured from materials WRAS approved for contact with drinking water
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Non-potable suitability
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Suitable for non-potable, process and general building-services water storage
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Insulation options
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Insulated and uninsulated options are available - confirm current availability and specification with Tricel
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Lid / cover configuration
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Close-fitting sealed lid - confirm against current Tricel product documentation
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Base / support requirements
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Level, adequately designed supporting base required; specific loading and construction against Tricel installation guidance and project structural design
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Access for installation
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Full, unobstructed delivery route required for the complete unit; must be assessed before ordering
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Fittings (inlet / outlet / overflow / warning)
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Standard provisions for inlet, outlet, overflow, warning pipe and drain; connection sizes and positions to suit tank model and project requirements.
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Internal components
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Internal stays/ties fitted where required by tank design; compartment divisions available on selected configurations.
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Important note
Final tank capacity, dimensions, fittings, insulation, access requirements, base/support arrangement and maintenance clearances must be confirmed against current Tricel technical information and the individual project specification before procurement.
03
BENEFITS OF ONE-PIECE TANKS
The core benefits of the one-piece format relate to manufacturing consistency, material performance and configuration flexibility rather than price or speed claims.
Wide standard size range
This covers most small- to medium-scale commercial cold water storage requirements without moving to a bespoke sectional build.
Factory-manufactured Construction
The tank is moulded and finished under factory conditions and arrives on site as one complete unit, rather than as panels requiring on-site assembly.
oN-SITE ASSEMBLY
Because there is no panel-by-panel build sequence, the on-site works are largely limited to positioning the tank, connecting pipework and commissioning, rather than a multi-stage assembly process.
Corrosion Resistance
GRP does not corrode in the way steel tanks can, which is relevant to long-term cold water storage in plant rooms and roof spaces — see tank sizes for capacity-specific detail and the material and durability section below for further discussion.
Quick & Efficient Installation
Where the full delivery route has been confirmed in advance, a one-piece tank can generally be positioned and connected in a single site visit.
Potable and non-potable storage
The same construction method serves drinking-water storage and general building-services (non-potable) storage, with materials in contact with drinking water WRAS approved.
Where the required capacity exceeds the one-piece range, or where the access route between the delivery point and the final location will not accommodate a complete moulded tank, a sectional GRP tank is normally the more practical option.
04
Applications and Industries Served
One-piece GRP water tanks are used wherever a building or site needs a self-contained cold-water storage unit within the standard 45 L–6,000 L capacity range and where the complete tank can be delivered to its final location. The specific water-storage requirement — and any sector regulation that applies to it — varies by building type and must be confirmed against the individual project specification.
Commercial Buildings
Office blocks, retail units and mixed commercial premises typically need a cold water storage tank (CWST) to maintain a buffer of potable water ahead of a pressure boosting set, or a break tank ahead of a heating or process circuit. A one-piece tank in a compact plant room or roof-level tank room is a common fit where capacity requirements are modest.
Healthcare
Hospitals, primary care centres and nursing homes require reliable cold water storage for domestic and clinical use, frequently alongside water-hygiene and Legionella risk-management programmes managed by the facility’s own competent person. A one-piece tank can suit smaller wards, satellite buildings or plant-room upgrades where a full sectional rebuild is not justified.
Hotels & Hospitality
Guest-occupied buildings need continuous cold water storage sized to occupancy and peak demand, often paired with a pressure boosting set to serve upper floors. Replacement of an ageing tank during a refurbishment programme is a frequent driver, discussed further under retrofit and replacement below.
Education
Schools and colleges need dependable cold water storage across term-time occupancy patterns, generally within plant rooms sized during the original building design — making access route confirmation particularly important on older campuses.
Industrial & Manufacturing
Process water, wash-down water and non-potable storage duties are common in industrial settings, alongside potable storage for welfare facilities. Tank material and fittings should be confirmed against the specific process fluid and any site-specific requirements.
Public Sector
Government offices, libraries and civic buildings have the same underlying cold water storage need as commercial buildings, generally procured through public sector tendering routes where compliance documentation and manufacturer history are evaluated as part of procurement.
Residential and mixed-use developments
Apartment blocks and mixed-use schemes typically require a communal cold water storage tank feeding a pressure boosting set to serve upper floors; capacity is sized to occupancy by the project’s M&E consultant.
Pharmaceutical and life-sciences facilities
These sites typically operate under strict water-quality and documentation regimes set by their own quality and regulatory teams. A standard one-piece GRP tank may form part of a wider water system, but sector-specific validation, testing and documentation requirements sit outside the tank itself and must be confirmed with the site’s own regulatory affairs or quality function.
Across every sector, the choice of a one-piece tank over a sectional alternative depends on the same underlying factors: required capacity, plant-room dimensions, and the physical access route — not the sector itself.
05
GRP ONE-PIECE WATER TANK RANGE
Tricel’s one-piece tank range is built around a shared core: single-unit GRP construction, factory assembly and a capacity band of 45 litres to 6,000 litres. Within that core, several configurations are available to suit different site conditions, water duties and maintenance requirements.
Most Common
Standard One-Piece Tank
A single-compartment GRP tank in the core 45 L–6,000 L range, factory-assembled and delivered ready to connect. Suits the majority of commercial cold water storage and break tank applications where site access allows a single-unit delivery.
Thermal Protection
Insulated One-Piece Tank
Built with additional insulation for tanks located outdoors, in unheated plant rooms or otherwise exposed to temperature extremes, reducing the risk of freezing or excessive warming of stored water.
NON-POTABLE APPLICATIONS
Uninsulated One-Piece Tank
Available in 10-gallon and 70-gallon sizes only, these uninsulated GRP tanks are suitable for non-potable water storage applications where thermal insulation is not required.
06
Category 5 GRP Break Tanks
A break tank provides a physical air gap between the incoming mains water supply and a downstream system, so that water in the downstream system cannot flow back and contaminate the public mains. A one-piece GRP tank can be specified in this role wherever a project requires a documented break between supply and downstream use.
Purpose
What a break tank does
Separates the public water supply from a downstream system by an open air gap, so the downstream system cannot draw contamination back into the mains under any backflow condition.
Typical Applications
Where It Is Typically Specified
Compliance & Regulations
Fluid category classification
Backflow risk is often described using a fluid category system (Fluid Category 5 being the highest risk), a concept originating in UK water regulations guidance.
The fluid category and air gap terminology referenced above is based on IS EN 1717, the Irish adoption of the European standard for protection against contamination of potable water systems by backflow. The required level of backflow protection for any installation should be confirmed with Uisce Éireann, the project’s consulting engineer, or Tricel Water before specifying a break tank or air gap arrangement.
07
Installing a GRP ONE-PIECE WATER TANK
Installing a Tricel one-piece GRP water tank is generally more straightforward than assembling a sectional tank on site, because the tank arrives as a single complete factory-manufactured unit. However, because the whole tank must reach its final position in one piece, access assessment has to happen before manufacture and delivery, not after the tank arrives on site.
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Requirement
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Guidance
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Confirm tank dimensions before ordering
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Check the overall length, width and height of the selected tank size against the full delivery route and final plant room location — not just the finished footprint.
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Survey the complete access route
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Doorways, corridors, stairwells, lift shafts, service openings and any changes of direction along the route into the plant room must be able to accommodate the tank's full dimensions.
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Check plant room access and clearance
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Confirm there is adequate space around the final tank position for connections, inspection and future maintenance access, in line with Tricel's product documentation.
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Prepare a level supporting base
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The tank must be installed on a suitably level, adequately designed supporting base capable of carrying the full water-filled weight of the tank, in accordance with Tricel's installation requirements and the project's structural design.
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Position the tank
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Once delivered, the tank is manoeuvred into its final position on the prepared base, with any lifting or handling carried out in line with site safety procedures.
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Complete plumbing connections
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Inlet, outlet, overflow and warning pipe connections are made in accordance with the tank's fitting positions and the project's water-services design.
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Allow for inspection and maintenance access
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Sufficient clearance should be maintained around and, where applicable, above the tank to allow safe access for future inspection, cleaning and maintenance.
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Commission, clean and disinfect as required
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Before the tank is brought into service, commissioning, cleaning and disinfection should be carried out in line with the project specification and relevant guidance for potable water storage.
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Installation should always follow Tricel’s current product instructions together with the project’s own mechanical and structural specification. Tricel does not publish generic loading values, slab thicknesses or clearance dimensions on this page, as these depend on the specific tank size and site conditions.
Specific base loading figures, minimum access clearances, lifting procedures and structural design criteria for individual one-piece tank sizes should be confirmed directly against current Tricel technical documentation and the project’s structural engineer.
For sites with genuinely restricted access — narrow doorways, tight stairwells or plant rooms that cannot receive a complete moulded tank — a sectional tank, assembled in place from individual panels, may be the more practical option. See sectional tank installation guidance and tank support and clearance requirements for comparison.
08
Compliance and Standards for One-Piece Water Tanks
Two certifications apply directly to Tricel’s one-piece tank range as manufactured: WRAS approval for materials in contact with drinking water, and ISO 9001 for the quality management system under which the tanks are produced. The table below sets out what each compliance area means for a one-piece tank specification, and flags where a claim needs independent verification rather than being stated as settled fact.
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compliance
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what it covers
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WRAS approval
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Confirms materials in contact with drinking water meet the requirements of the Water Regulations Approval Scheme, relevant where a one-piece tank stores potable water.
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ISO 9001
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Confirms the tank is manufactured under a certified quality management system per ISO 9001, covering consistency of manufacture rather than a specific product feature.
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FM Approval
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Applies to Tricel's fire-protection tank range, not to one-piece cold water storage tanks. Fire sprinkler storage duty is covered on the Sprinkler Tanks page.
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Public water supply connection
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Connection to the public water network in Ireland falls under Uisce Éireann; confirm any connection or backflow-prevention requirement for a specific site with Uisce Éireann or the project's consulting engineer.
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Site installation and lifting safety
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General site safety during tank delivery, lifting and installation is covered by Health and Safety Authority guidance, not by the tank manufacturer.
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Irish/EN tank construction standards
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Tricel does not currently cite a specific EN or Irish standard number for one-piece tank construction on its live site; check current applicable standards via NSAI before citing one in a formal spec
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Water byelaws / plumbing regulations
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Confirm applicable Irish building, plumbing, and backflow prevention requirements with Uisce Éireann and the project engineer rather than relying solely on UK water byelaw guidance.
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Compliance note
The tank alone does not determine compliance. Tank configuration, stored-water use, backflow protection, access, maintenance and the wider water-services installation must all be considered at design stage.
For Category 5 applications, the required Type AA or Type AB air-gap arrangement should be confirmed by the project’s water-services designer or M&E engineer.
09
One Piece vs Sectional GRP Water Tanks
Choosing between a one-piece or sectional GRP tank depends on required capacity, site access, available space, installation programme, maintenance requirements and the project specification — no single format is universally the correct choice.
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Requirement
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One Piece
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Sectional
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Capacity range
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45L – 6,000L
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1,000 L – 4.6 million+ L
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Construction
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Single moulded GRP unit, factory-assembled
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Bolted GRP panels, assembled on site
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Delivery / access requirement
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One full-size delivery to the installation point
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Panels carried in individually, suited to restricted access
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Footprint
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Fixed, per standard size
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Configurable, built to project footprint
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Typical use case
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Sites where a full single unit cannot be delivered but a full sectional build is not needed
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Large capacities or sites with restricted access
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10
GRP one-piece Water Tank Case Studies - Ireland & UK Installations
Explore one-piece GRP water tank installations delivered across Ireland and the UK for education, commercial, residential, industrial and public-sector developments. These case studies showcase how Tricel’s one-piece tank range provides reliable water storage where rapid installation, site access and long-term performance are key project requirements.
Top 3 Case Studies
Tricel
50 Custom One-Piece Water Tanks for J.PAO AND CO. LTD
Food & Beverage
London, UK
To manufacture and install 50 custom one-piece GRP water tanks for J. Pao and Co. Ltd’s new food production facility.
Tricel
Hoe Valley Secondary School Water Tank Installation
Education
Surrey, UK
Bespoke sectional and TIF water storage tanks supplied for Hoe Valley School, maximising capacity within a restricted plant room.
Tricel
The Shard Water Tank Installation, London
High-Rise & Multi-Storey
London, UK
Seven GRP water tanks supplied and installed across multiple floors of The Shard, supporting its vertical water supply requirements.
other related projects
Tricel
Gramercy Towers C-Shaped TIF Tank Installation
Industrial
Wales, UK
A bespoke C-shaped TIF tank designed around plant-room columns to maximise wet-riser water storage capacity.
Tricel
Sprinkler Water Storage – Prince of Wales Drive, Battersea
Industrial
London, UK
A bespoke 56,303-litre E-shaped GRP sectional sprinkler tank, designed to work around plant-room columns, curved walls and confined-space requirements.
frequently asked questions
How can I confirm a one-piece tank will physically reach its installation point before it's manufactured?
Measure the complete delivery route — external access, doorways, corridors, stairwells, lifts and the final plant-room opening — against the tank’s overall dimensions, not just the floor area of the room it will occupy. Share these measurements with Tricel before manufacture to confirm fit.
Can a one-piece GRP tank be used to replace an existing failed steel or concrete tank in the same plant room?
Yes, in principle, provided the required capacity sits within the 45 L–6,000 L one-piece range and the access route allows the replacement unit to reach the same location. Existing pipework, base and plant-room dimensions should be checked against the new tank before removing the old one.
How far in advance should a one-piece tank be ordered on a construction programme?
Lead times vary depending on tank size, insulation specification, ancillary fittings, and current manufacturing capacity, and are not published as a fixed figure on the current Tricel Water website. Confirm current manufacturing and delivery lead times with the Tricel Team when requesting a quotation.
Does specifying insulation change the tank's external dimensions I need to check against access?
Yes. An insulated one-piece tank is generally larger overall than the equivalent uninsulated unit because insulation is applied to the exterior. Confirm the insulated outer dimensions — not the nominal tank dimensions — against your access route and plant-room space before finalising an order.
Can a facility keep operating while a one-piece tank is taken offline for inspection or cleaning?
Service continuity depends on the overall system design. A standard single one-piece tank has no inherent redundancy, so continuity during maintenance or outages typically requires standby storage, a duplicate tank, or an alternative supply arrangement. These requirements should be agreed with the project’s M&E engineer, facilities team, or system designer during the design stage.
Who is responsible for confirming Irish regulatory compliance for a one-piece tank installation?
Responsibility for confirming applicable Building Regulations, water-byelaw, backflow-protection and water-hygiene requirements rests with the project’s consulting engineer or water-services designer, not with the tank manufacturer. Tricel confirms only the certifications it holds directly — see Compliance for One-Piece GRP Water Tanks in Ireland above.
What tolerance or loading capacity does the supporting base need to provide?
A one-piece tank must be installed on a level, adequately supporting base designed in accordance with Tricel’s installation requirements and the project’s structural design. Base tolerances, load distribution, and support requirements should be confirmed against current Tricel technical documentation and the project engineer’s specification before installation.
What warranty applies to a Tricel one-piece GRP tank?
Tricel’s specific warranty period and warranty terms for the one-piece tank range are not currently published on the referenced page. Request the latest warranty documentation directly from Tricel Water when specifying, tendering, or ordering a tank to ensure the information reflects current product terms and conditions.
Request a Quote for a GRP One-Piece Storage Tank
Send Tricel your required nominal capacity, potable or non-potable duty, available footprint, room/access dimensions, insulation requirement, inlet/outlet needs, break-tank requirement (if applicable), standard preference, base/site information and any project drawings you have, and Tricel’s technical sales team will recommend a suitable one-piece, sectional configuration.