Pressed Steel Sectional Water Tank | BS 1564 | ZENTVO
BS 1564 · Modular Panels · Plant Room Ready

Pressed Steel Sectional
Water Tank

A bolted modular tank built from 1,220 × 1,220 mm pressed steel panels — designed to pass through an 800 mm door. Hot-dip galvanized to BS EN ISO 1461. WRAS-certified for potable service, LPCB & FM-approved for fire reserve.

Request a 24-hour Quote See Door / Panel Guide
WRAS BS 6920 LPCB LPS 1276 FM Global DS 3-2 BS EN ISO 1461
Pressed steel sectional water tank — panel detail and installation
1 – 1,500 m³Capacity range
30 + yrsDesign life
24 hGA drawing

Quick Engineering Summary

Reference standard
BS 1564
De facto global baseline
Standard module
1,220 × 1,220 mm
Half-panel: 610 × 1,220 mm
Zinc coating
70–85 μm
BS EN ISO 1461 hot-dip galv.
Height options
1 – 4 m
Whole-panel multiples of 1 m
ItemZENTVO specification
Reference standardBS 1564 (pressed steel sectional rectangular tanks) — de facto industry reference
Standard panel module1,220 × 1,220 mm (imperial) or 1,000 × 1,000 mm (metric)
Half / quarter panels1,220 × 610 mm, 610 × 610 mm — for door-restricted sites
Panel constructionHot-pressed pyramidal stiffening pattern, peripheral flange
Coating systemHot-dip galvanized to BS EN ISO 1461, typical 70–85 μm zinc
Optional internal liningWRAS-approved epoxy or food-grade liner for potable / process water
Panel thickness3 mm top course → 5 / 6 mm bottom course (height-dependent)
Tie-rod reinforcementInternal stays triggered at H ≥ 2 m; cross-stays at H ≥ 3 m
Capacity range1 m³ – 1,500 m³ (single tank); larger via tank farm
Governing standardsBS 1564, BS EN ISO 1461, WRAS BS 6920, LPCB LPS 1276, FM Global DS 3-2
Engineering turnaroundCAD/GA drawings within 24 hours of confirmed inputs
Typical delivery15–35 working days FOB after drawing approval

The format exists for one engineering reason: a complete welded tank cannot be carried through an 800 mm building door or fitted into a basement plant room with a 2.4 m ceiling. By breaking the tank into 1 m² (or smaller half-panel) sections, the same storage volume can be installed inside a building, on a rooftop, or in any restricted-access location — and dismantled later without cutting. For larger outdoor cylindrical tanks, see our bolted steel water tank and hot-dip galvanized tank product lines.

Access control matters because panel size drives labour, installation route, flange selection and gasket count. If the access survey is wrong, the tank can pass engineering review and still fail on delivery because full panels cannot physically reach the plant room.

AuthorXu Alex, ZENTVO product documentation reviewer.
Technical reviewReviewed by Xu Alex, ZENTVO product documentation reviewer.
Last updatedJuly 1, 2026. Standard references and internal links checked before publishing.

The Reason This Tank Exists: Door, Panel, Plant Room

The defining selection question for a pressed steel sectional tank is not capacity — it is whether the panels can physically reach the installation position. The table below is the single most useful reference in this document for building services consultants and M&E contractors.

Access Route Assessment

Check this before specifying panel size. The BS 1564 1,220 mm panel diagonal = 1,726 mm — it will not fit through an 800 mm door.

Standard single door
800 mm clear opening
610 mm half-panel only
Half-panel
Double door
1,500–1,800 mm clear
Full 1,220 mm panel on edge
Full panel ✓
Goods lift
1,400 × 2,000 mm typical
Full panel vertical
Full panel ✓
Stair turn (residential)
900 mm clear at landing
Half-panel + extra labour
Half-panel
Plant room ceiling
2.4 m typical
Tank H ≤ 2 m + 400 mm working space
Limit H to 2 m
Basement parking ramp
2.1 m clearance typical
Trolley-mounted half-panels
Quarter-panels

Panel weights: 1,220 × 1,220 × 5 mm = ~50 kg (two-person carry). 610 × 1,220 × 5 mm half-panel = ~25 kg — within one-person manual handling limits.

Access calculation: the BS 1564 module is 1,220 × 1,220 mm, and the full-panel diagonal by Pythagoras is √(1,220² + 1,220²) = 1,725 mm, so an 800 mm door cannot pass the full panel. Half-panel width is 610 mm, so it passes the clear opening, but diagonal handling still needs landing clearance. Recommendation: use 610 × 1,220 mm half-panels for openings below 1,000 mm and quarter-panels for tight stair turns.

Internal-Flanged vs Externally-Flanged Construction

This is the most common technical distinction in pressed steel sectional tank tenders and is rarely explained on supplier sites. ZENTVO supplies both — the decision belongs at the specification stage, not the delivery stage.

Traditional · BS 1564

Internal-Flanged

Bolts and flanges inside the tank, in contact with water. Internal fastenings visible in wetted zone.

  • Higher cleaning effort — fastenings collect sediment
  • Acceptable for fire reserve and industrial utility
  • Bolts must be galvanized + sealed (corrosion risk)
  • Tie-rods visible and wetted
  • Lower cost — easier fabrication
1.00× baseline CAPEX
Best for: fire reserve, general utility, industrial, construction/temporary use
Recommended for potable

Externally-Flanged

Bolts and flanges outside the wetted zone — smooth, wipe-clean internal walls preferred for hygiene-critical service.

  • Smooth internal surface — easiest mechanical cleaning
  • Preferred for potable, hospital, food & pharmaceutical
  • Bolts always dry — lower corrosion risk
  • Eliminates wetted tie-rod concern
  • Required for some NHS / healthcare specs
1.20–1.30× vs internal-flanged
Best for: potable cold water, hospital, education, food process

ZENTVO default recommendation: externally-flanged for potable, hospital and food applications. Specify at purchase order — not at delivery.

Professional Use Cases

Basement Plant Room

Constraints: 800–900 mm door, 2.4 m ceiling, drain tray required below tank.

ZENTVO solution: 610 × 1,220 mm half-panels through door, internally-flanged for fire reserve or externally-flanged for domestic cold water, 2 m max height, drip tray + leak-detection probe. For potable duty requires WRAS-certified epoxy internal lining.

Internal-flanged or Externally-flanged

Rooftop Water Storage

Constraints: Structural slab load (≈1,000 kg/m² per metre of water depth), wind exposure, maintenance access.

ZENTVO solution: capacity sized to structural engineer’s slab review; externally-flanged for hygiene; HDG + epoxy topcoat for coastal high-rise per ISO 12944 C4–C5-M; rooftop access ladder per OSHA 1910.27 / BS EN ISO 14122. See our foundation requirements guide for load calculations.

Externally-flanged preferred

Fire Reserve Storage

Constraints: Usable fire volume, low-water alarm, pump suction submergence.

ZENTVO solution: LPCB LPS 1276 or FM Global DS 3-2 approved configuration; vortex-suppressing pump outlet; minimum operating water level fixed at PO stage; effective fire volume documented on GA drawing — not just nominal volume. Standard internal-flanged construction is acceptable for fire reserve with hot-dip galvanized panels.

LPCB · FM Global

Industrial / Process Water

Constraints: Water chemistry, temperature, possible cleaning chemicals.

ZENTVO solution: water analysis review before quotation; coating route selected per chemistry. Standard HDG for soft water; epoxy-lined coated steel for chlorinated or aggressive water; pH must be confirmed within the 6–8 galvanizing service envelope.

Chemistry review required

Construction / Temporary Site Water

Constraints: Re-deployable, fast erection, dismantling without damage. ZENTVO solution: bolted-only construction with reusable EPDM gaskets; typical 50 m³ tank erected in one day by a 2-person crew; tank can be dismantled, gaskets renewed, and re-erected on the next site. Compare with our bolted steel tank for larger outdoor volumes.

Re-deployable

Pressed Steel Sectional vs GRP Sectional vs Welded Steel

The three modular formats most often cross-compared in M&E tenders. For projects where water chemistry, chlorine or industrial cleaning chemicals drive coating choice, review the coated steel tank specification as an alternative route.

Criterion Pressed Steel Sectional GRP Sectional Site-Welded Steel
Standard module1,220 × 1,220 mm1,000 × 1,000 mm (metric)N/A — built on site
Panel weight (full)~50 kg (5 mm)~15 kgN/A
Corrosion resistanceHDG + WRAS gaskets or externally-flanged + epoxyInherent — non-corrodingInternal coating required, periodic repainting
HygieneExternally-flanged preferredExcellentWelded smooth — best mechanical hygiene
Strength under shockHigh — steelMedium — brittle in cold impactHigh, but welded joint risk
Service life30+ years25+ years30+ years if coating maintained
Re-deployabilityHigh — bolted disassemblyHigh — bolted disassemblyNone — must be cut up
Relative CAPEX1.00× (baseline)1.10–1.25×0.80–0.95× (site weld only)
Best fitFire reserve, plant room, restricted accessPotable rooftop, hygiene-critical, lightweightOpen-site large tanks (>1,500 m³)

Failure Modes to Design Against

Specifying a pressed steel sectional tank is not enough — the project must engineer against these documented failure modes. See also our foundation requirements guide for bolted and sectional tanks.

🔩

Joint leakage at lap

Foundation out of level; gasket misalignment; uneven bolt torque

Prevention

Foundation ±3 mm/3 m; calibrated torque 40–60 N·m M12 / 80–120 N·m M16; progressive sequence per GA drawing

📐

Panel bulging at mid-height

Insufficient panel thickness for hydrostatic head; missing tie-rod

Prevention

Bottom course 5–6 mm at H ≥ 3 m; internal stays at H ≥ 2 m; cross-stays at H ≥ 3 m

⚠️

Corrosion at submerged bolts

Internal-flanged with untreated bolt heads wetted at all times

Prevention

Specify externally-flanged, or stainless A2/A4 bolts + sealed caps in the wetted zone

🚪

Tank cannot enter plant room

Panel size not checked against door or stair opening

Prevention

Survey access route before final panel size — half-panel standard for door ≤ 1,000 mm clear

💧

Failed potable approval

Non-WRAS gaskets or bolt caps despite WRAS panel coating

Prevention

Confirm WRAS BS 6920 certification for all wetted components — not only the panels

🔧

Nozzle leakage / stress

Unsupported external pipe pulling on tank wall

Prevention

Independent pipe support within 1 m of nozzle; reinforced nozzle plate for DN ≥ 80

Quality & Inspection Points

Stage 1

Steel Substrate

Composition and thickness verified by EN 10204 3.1 mill certificate

Stage 2

Press Forming

Pyramidal stiffening geometry and flange flatness checked on jig

Stage 3

Galvanizing

Zinc thickness 70–85 μm per BS EN ISO 1461, magnetic gauge measurement

Stage 4

Bolt / Gasket

Material and dimension per EN 10204 2.2 / 3.1; WRAS cert checked where required

Stage 5

Trial Assembly

Critical corner panels trial-fitted; documented in pre-shipment inspection record

Stage 6

Packing

Mark map keyed to GA drawing; edge protection on all flanges; container loading plan issued

BIM / Revit family file (Revit .rfa + IFC) available on request for M&E tender submission — drop straight into your BIM model. Request via ZENTVO Resources or at PO stage.

Specification Checklist & Minimum Technical Submittal Package

For BIM-driven M&E projects and EPC tenders, ZENTVO ships:

  • General arrangement drawing (PDF + DWG)
  • Panel layout drawing with mark map
  • Foundation reaction drawing
  • Panel mill certificate (EN 10204 3.1)
  • HDG coating certificate (BS EN ISO 1461)
  • WRAS / LPCB / FM Global certificate where applicable
  • Bolt, gasket and tie-rod schedule with material certs
  • Nozzle schedule with reinforcement details
  • Flange specification confirmation
  • Container loading plan
  • Installation manual (English; translated on request)
  • BIM family file (Revit .rfa / IFC) on request

Pressed Steel Tank RFQ Checklist

Send these twelve RFQ inputs to request a quote within 24 hours. The highlighted field is the single most important input because it determines full vs half panels and directly affects price and installation time.

  • 1
    Usable capacity (m³)
  • 2
    Tank room L × W × H clear internal
  • 3
    Door / lift / stair clear opening (the access bottleneck)
  • 4
    Indoor / outdoor / rooftop / basement
  • 5
    Water duty (potable / fire / industrial)
  • 6
    Required certification (WRAS / LPCB / FM Global / local)
  • 7
    Preferred flange type (internal cost-optimised / external hygiene)
  • 8
    Foundation type and load capacity
  • 9
    Nozzle schedule (qty, DN, orientation)
  • 10
    Required accessories (ladder, level gauge, drip tray, alarm)
  • 11
    Country of installation
  • 12
    Required FOB date

Frequently Asked Questions

What is the standard panel size of a pressed steel sectional water tank?
1,220 × 1,220 mm (imperial, BS 1564) or 1,000 × 1,000 mm (metric). Half-panels (610 × 1,220 mm) and quarter-panels (610 × 610 mm) are available for door-restricted plant rooms. ZENTVO confirms panel size after the access survey because this controls handling weight, labour and installation route.
Will a full 1,220 mm panel pass through a standard door?
No. A standard single door has 800 mm clear opening; the diagonal of a 1,220 × 1,220 mm panel is 1,726 mm. The panel cannot be angled through. Specify 610 mm half-panels for door openings under 1,000 mm — the single most important check before procurement.
What standard governs the design?
BS 1564 — Pressed Steel Sectional Rectangular Tanks is the historical reference and remains the de facto industry baseline worldwide. Hot-dip galvanizing is to BS EN ISO 1461. Potable applications require WRAS BS 6920 certification of all wetted components. Fire reserve requires LPCB LPS 1276 or FM Global Data Sheet 3-2 approval.
What is the difference between internal-flanged and externally-flanged construction?
In internal-flanged (traditional BS 1564) tanks, the bolts and gaskets sit inside the tank, wetted at all times. In externally-flanged tanks, the bolts and flanges are outside the wetted zone, leaving smooth internal walls. Externally-flanged costs 20–30% more but is preferred for potable, hospital and food-grade applications because of easier cleaning and lower bolt-corrosion risk.
Can a pressed steel sectional tank be used for drinking water?
Yes, when all wetted components — panel coating (or HDG + WRAS epoxy), gaskets, sealants, bolts and tie rods — carry WRAS BS 6920 certification. ZENTVO supplies certificate numbers at PO stage; always ask for the wetted-parts certification list, not only the panel certificate.
Is a pressed steel sectional tank suitable for fire reserve?
Yes. ZENTVO supplies LPCB LPS 1276 and FM Global DS 3-2 compliant configurations. The effective fire volume (between low-level alarm and outlet, with anti-vortex plate) is documented on the GA drawing, not just nominal capacity. For FM-insured sites, confirm the approval route before PO because listing status changes the acceptable tank configuration.
What causes leakage in sectional tanks?
In order of frequency: (1) foundation out of level, (2) gasket displaced during installation, (3) bolt torque drift or uneven sequence, (4) external pipework pulling on the nozzle. Foundation flatness ±3 mm / 3 m and progressive torque per the GA drawing eliminate the first three. See our foundation requirements guide for site preparation details.
What capacity range does ZENTVO supply?
1 m³ to 1,500 m³ in a single pressed steel sectional tank; larger volumes are delivered as tank farms with shared piping and instrumentation. For outdoor tanks above 1,500 m³, see the bolted steel water tank range.

Sources & Technical Review

This page combines ZENTVO manufacturing documentation with public standard and approval references. Final compliance should be checked against the project edition named by the engineer of record, consultant or local authority.

  • BS 1564:1975 — pressed steel sectional rectangular tanks reference.
  • ISO 1461 — hot-dip galvanized coatings on fabricated iron and steel articles.
  • WRAS Material Approvals — potable-water material approval route for relevant components.
  • LPCB LPS 1276 — approval standard for sectional tank systems used in fire protection.

Ready to move forward?

ISO 9001 · ISO 14001 · WRAS BS 6920 · LPCB · FM Global · BS EN ISO 1461 · NSF/ANSI 61 · CE. GA drawing returned within 24 hours of complete inputs.

Specifying the M&E schedule?

Request the ZENTVO Pressed Steel Sectional Tank BIM family file (Revit .rfa + IFC) to drop into your model.

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Comparing formats?

Download the Pressed Steel vs GRP Sectional vs Welded Steel comparison — single-page for your tender appendix.

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