Key Takeaways
A compliant diesel bund begins with a clear understanding of the applicable fire-safety and environmental controls. Sound calculations, coordinated drawings, and disciplined inspection records reduce the risk of costly revisions.
- Confirm the applicable SCDF, NEA, and site-specific requirements before finalising the design.
- Base the bund calculation on the correct tank or shared-storage volume.
- Detail floors, walls, joints, penetrations, drainage, and access as one containment system.
- Coordinate fuel systems, generators, electrical equipment, and emergency controls.
- Keep installation, inspection, maintenance, and modification records up to date.
Establish the SCDF and NEA requirements before designing the bund
Diesel bunding is not simply a concrete enclosure placed around a tank. It forms part of a wider submission involving fire safety, environmental protection, tank capacity, generator operation, and the physical constraints of the site. Before drawings are developed, the project team should establish which authority requirements apply and what information must support the application. Stellar Structures can bring engineering, architectural, and regulatory submission coordination into the early design discussion, helping prevent avoidable changes later.
Determine which diesel storage and fire-safety requirements apply
Start by identifying the tank type, fuel, capacity, location, and connection to the generator system. Fire-safety requirements may depend on how diesel is stored, how it is transferred, and whether the installation is within or beside an occupied building. Review the relevant submission pathway before selecting wall dimensions or equipment positions, because a bund that satisfies a simple volume calculation may still conflict with access, ventilation, separation, or emergency-response requirements.
Distinguish SCDF approval requirements from NEA environmental controls
SCDF considerations generally centre on fire safety, emergency access, ignition control, detection, isolation, and the safe arrangement of fuel-handling equipment. NEA-related controls concern environmental protection, spill prevention, contaminated water, waste handling, and pollution risk. The two areas overlap at the bund, but they should not be treated as interchangeable; each requirement should be traced to the drawing, calculation, specification, or procedure that demonstrates compliance.
For projects involving larger aboveground storage tanks, external guidance can provide useful context, but it should not replace Singapore-specific advice. A diesel tank approval guide illustrates why plan review, inspection, and installation documentation need to be considered before construction rather than after the tank arrives on site.
Confirm tank capacity, storage location, and generator classification
Obtain the approved or proposed tank data sheet, not just a rounded capacity stated in an email. Record the working capacity, nominal capacity, number of tanks, tank dimensions, fuel-line arrangement, and whether the tank is integral to or separate from the generator. The location should then be checked against building use, occupied areas, exits, service routes, ventilation openings, and areas where a spill could migrate.
Identify site-specific constraints, codes, and authority consultation needs
Existing slabs, drainage lines, underground services, property boundaries, neighbouring structures, and maintenance routes can all affect the design. A site inspection should confirm levels and identify low points where fuel or contaminated water could travel. Where the arrangement is unusual, early consultation with the relevant professionals and authorities is preferable to relying on an assumption that may be challenged during submission review.
Calculate the 110% bund capacity correctly
The 110% rule is often described as a quick multiplication exercise, but the design volume must correspond to the actual containment arrangement. The calculation should state what volume is being contained, which tank governs, how internal objects affect usable capacity, and what additional allowances apply. A clear calculation sheet is especially valuable when several tanks share one enclosure or when the bund has irregular geometry.
Apply the 110% rule to the largest tank or applicable storage volume
For a single tank, begin with the tank capacity used by the applicable requirement and multiply it by 1.10. Do not substitute the generator’s daily consumption, the anticipated fill level, or an unverified operating volume for the required storage volume. If the authority or project specification requires a different basis, state that basis explicitly and retain the supporting reference in the submission record.
Account for multiple tanks, shared bunds, and internal partitions
A shared bund needs a deliberate rule for determining the governing release scenario. Depending on the applicable requirement and arrangement, the design may need to contain the largest tank or a larger combined volume. Internal partitions can divide storage areas, but they should not be used to reduce the required capacity without a defensible hydraulic and regulatory basis.
The following schedule makes the design logic easier to review. It should be accompanied by dimensions and assumptions, rather than presented as a standalone conclusion.
| Item | Information to record | Why it matters | Typical design check |
|---|---|---|---|
| Tank capacity | Nominal and applicable storage volume | Establishes the calculation basis | Confirm against the tank data sheet |
| Bund geometry | Internal length, width, and wall height | Determines gross containment volume | Use clear internal dimensions |
| Internal displacement | Tank, supports, plinths, and fixed equipment | Affects usable volume | State included and excluded items |
| External inflow | Rainfall or firefighting water allowance | May increase required volume | Confirm the project assumption |
After the gross volume is calculated, compare the usable capacity with the governing requirement. The reviewer should be able to follow the calculation from the tank schedule to the plan and section without reconstructing the arithmetic.
Deduct or include displacement from tanks, supports, and equipment correctly
A tank and its supports occupy space inside the bund, so the relationship between gross and net capacity must be stated. Use the actual immersed or enclosed displacement relevant to the containment geometry, and do not deduct items that are not permanently within the bund. Conversely, do not claim the full geometric volume if a raised floor, equipment plinth, partition, or other fixed obstruction reduces the available space.
Allow for rainfall, firefighting water, and freeboard where required
An uncovered bund may receive rain, while firefighting activity can introduce additional water into the containment area. Whether these allowances are required depends on the project, authority direction, and design arrangement, but they should never disappear through an unstated assumption. Show the allowance, drainage control, and freeboard in the calculation so the design remains understandable during review.
Design the bund structure for containment and durability
A bund must remain capable of containing diesel after construction, settlement, weathering, maintenance work, and ordinary service access. Its performance depends on the floor, walls, joints, penetrations, coatings, and interfaces with adjoining construction. A visually substantial wall is not enough if a crack, drain, cable route, or pipe sleeve creates an unsealed escape path.
Select suitable concrete, coatings, membranes, and joint-sealing systems
Material selection should reflect diesel exposure, weather, cleaning methods, substrate movement, and the expected maintenance regime. Concrete mix, reinforcement, curing, surface preparation, protective coatings, membranes, and sealants should be specified as a compatible system. Product suitability should be confirmed from technical data and installation instructions, rather than inferred from a general statement that a material is waterproof.
Detail wall height, floor slope, penetrations, and construction joints
Plans and sections should show the clear internal dimensions, wall height, floor build-up, falls, upstands, construction joints, movement joints, and sealant details. A slight floor fall can help direct liquid toward a controlled collection point, but the low point must not become an unprotected drain. Sections are often more useful than plan notes because they reveal changes in level and the relationship between the tank base and the containment wall.
Prevent seepage through cracks, drains, cable routes, and pipe sleeves
Every penetration should have a defined sealing detail and installation responsibility. Pipe sleeves, cable routes, conduits, drainage outlets, and interfaces with existing slabs deserve particular attention because they are common weak points. Where a drain is necessary, it should discharge only through a controlled arrangement that prevents an uncontrolled diesel release or contaminated water from entering the stormwater system.
Design access points without creating spill escape paths
Maintenance access should be practical without reducing the containment height. Removable panels, steps, ramps, thresholds, and gates need to preserve the sealed line around the bund. If a ramp is unavoidable, its level changes and edge details should be shown clearly, with a method for preventing liquid from bypassing the wall during a spill.
Integrate the bund with diesel tanks and generator systems
The bund works only when the connected fuel system is coordinated with it. Tank nozzles, flexible connections, pipe supports, valves, vents, overflow arrangements, generator skids, and electrical routes can all affect containment and emergency response. Treat the tank and generator as a connected installation, while keeping the emergency spill boundary clear and inspectable.
Coordinate tank nozzles, fuel lines, valves, vents, and overflow protection
The drawings should identify every fuel connection and its direction of flow. Fill points, supply and return lines, isolation valves, vents, level indicators, flexible connectors, and overflow protection should be checked for access and potential leak locations. Components outside the bund should not create an unexamined section of pipework where a failure could discharge fuel beyond the intended containment area.
Separate normal drainage from emergency spill containment
Rainwater removal and spill containment serve different purposes. A normal drainage route may be acceptable only when it can be isolated, inspected, and managed in accordance with the project requirements; it must not function as an always-open escape route for diesel. The operating procedure should explain who checks the bund, how water is assessed, and when isolation or waste disposal is required.
Position generators, electrical equipment, and ignition sources safely
Generator placement should account for hot surfaces, exhaust discharge, electrical equipment, ventilation, refuelling, and emergency access. Cable routes and electrical penetrations should not compromise the bund seal. Equipment clearances should be checked against the manufacturer’s information and the applicable fire-safety requirements, with the final arrangement shown consistently across architectural, mechanical, and electrical drawings.
Provide access for inspection, refuelling, maintenance, and emergency response
A technically compliant bund can still be impractical if personnel cannot inspect the tank, operate valves, remove rainwater, or reach emergency isolation points. Keep service paths clear and provide enough room for safe maintenance activities. For a useful overview of capacity planning, a generator fuel tank guide can help frame questions about emergency stock, supply lead time, and operational requirements, while the project design must still be verified for its actual site and authorities.
Prepare complete diesel storage tanks and generator submissions
A submission should tell one consistent story: what is being installed, where it is located, how it operates, and how a release will be contained. Missing details tend to create questions that delay review, even when the underlying design is sound. For Diesel Storage Tanks & Generator Submissions, completeness is part of the technical design, not an administrative afterthought.
Compile tank drawings, bund calculations, layouts, and equipment schedules
Assemble the tank data sheet, general arrangement, bund plan, sections, elevations, capacity calculation, fuel-system schematic, equipment schedule, and relevant specifications. Include the design assumptions used for capacity, displacement, rainfall, freeboard, drainage, and access. File names and revision numbers should make it obvious which documents form the current submission set.
Show containment details clearly on plans, sections, and enlarged views
The reviewer should not have to search across several drawings to understand the spill boundary. Identify wall heights, floor levels, penetrations, joints, drain controls, thresholds, and tank supports at an appropriate scale. Where a detail is difficult to read on the general arrangement, provide an enlarged view and reference it directly from the plan or section.
Include fire-safety, ventilation, detection, shutoff, and emergency provisions
The package should address the controls that make the installation manageable during both normal operation and an incident. Depending on the project, this may include ventilation, detection, emergency shutoff, isolation valves, access, equipment separation, and response provisions. Each item should be located on a drawing or described in a coordinated specification, rather than mentioned only in a general note.
Align architectural, structural, mechanical, electrical, SCDF, and NEA documents
Coordination is where an integrated design team adds practical value. Stellar Structures provides engineering, architectural, and interior design solutions alongside regulatory submissions and approvals, so the documentation should be reviewed as a single package rather than as disconnected disciplines. Before issue, compare tank dimensions, wall positions, levels, penetrations, equipment tags, and notes across every relevant sheet.
Avoid design and documentation issues that trigger rejections
Most review comments are easier to prevent than to answer after submission. They often arise from a mismatch between the calculation and the drawing, a missing drainage assumption, or an access arrangement that looks acceptable in plan but fails in section. A short internal review focused on containment and authority questions can expose these weaknesses before they become formal comments.
Correct undersized bunds and unsupported 110% calculations
Check the calculation basis first, then recalculate the usable internal volume from the dimensions shown. Confirm whether the governing tank, shared storage arrangement, displacement, rainfall, and freeboard have been treated consistently. A result without a stated method is difficult to defend, even if the final number appears larger than 110%.
Resolve missing drainage controls, rainwater assumptions, and spill pathways
Do not leave the reviewer to infer whether a drain is normally open, manually operated, or connected to a controlled collection system. Identify low points, discharge routes, isolation arrangements, and the procedure for rainwater removal. The same review should trace a hypothetical spill from each tank connection to the edge of the site, checking that no opening or level change defeats containment.
Prevent inconsistencies between drawings, specifications, and tank data sheets
A tank capacity on the schedule that differs from the calculation is an immediate credibility problem. Other common conflicts include mismatched wall heights, omitted pipe penetrations, different equipment tags, and notes that describe a drain not shown on the plan. Use a coordinated document register and conduct a line-by-line comparison before issuing the package.
Address access, clearance, labelling, and maintenance concerns before submission
Reviewers and future operators need to know how the system will be used, inspected, isolated, and maintained. Show access routes, valve locations, clearance zones, labels, emergency controls, and areas needed for tank or generator servicing. These details also help clients and contractors price the work accurately instead of discovering operational constraints during construction.
Verify, maintain, and document bund compliance after installation
Approval is not the end of compliance. Construction quality, equipment changes, accidental damage, and accumulated rainwater can all affect the bund’s performance after handover. The owner, contractor, and design team should agree on inspection responsibilities and retain evidence that the installed work matches the approved arrangement.
Inspect concrete, coatings, joints, penetrations, and drainage controls
Inspect the containment floor and walls for cracking, honeycombing, impact damage, coating failure, open joints, and unsealed penetrations. Check that drain covers, valves, collection points, thresholds, and access panels are installed as documented. Photographs, marked-up drawings, product records, and rectification notes create a useful baseline for future inspections.
Test leak-tightness and verify emergency isolation arrangements
The testing method should suit the construction and be agreed with the responsible professionals before it begins. Verify that isolation valves can be reached and operated, that controls are identified, and that the emergency arrangement matches the approved drawings. Any leakage, defective seal, or inaccessible control should be corrected and recorded before the system is placed into normal service.
Establish procedures for rainwater removal, spill response, and waste disposal
The operating procedure should distinguish clean rainwater from water that may be contaminated by diesel. It should cover inspection frequency, isolation before drainage, spill response materials, escalation contacts, contractor responsibilities, and lawful handling of contaminated waste. Staff should know that opening a drain without checking the liquid can turn a contained incident into an environmental release.
Keep inspection records and update approvals after system modifications
Retain inspection dates, findings, photographs, test results, repairs, waste records, and responsible personnel. Any change to tank capacity, fuel lines, generator location, bund geometry, drainage, or emergency controls should trigger a review of the approved documents. Stellar Structures’ one-stop approach across design and regulatory submissions is most useful when modifications are treated as coordinated project changes rather than isolated site work.
Conclusion
A compliant diesel bund is the result of joined-up decisions: the right regulatory basis, a transparent 110% calculation, durable containment details, coordinated generator interfaces, and reliable records after installation. When these elements are developed together, Diesel Storage Tanks & Generator Submissions become clearer to review and easier to build, operate, and maintain.
Frequently Asked Questions
What does the 110% bund rule mean?
It generally means the bund should provide containment equal to at least 110% of the applicable governing tank or storage volume, subject to the requirements and assumptions accepted for the project.
Should a shared bund be sized for every tank?
The answer depends on the applicable requirement and the physical arrangement. The submission should clearly identify the governing release scenario and explain how shared storage, partitions, displacement, and additional water allowances were treated.
Can a bund have a drain?
A drain may be possible when it is properly controlled, isolated, inspected, and connected to an acceptable discharge or collection arrangement. An uncontrolled open drain can provide a direct spill pathway and should not be assumed acceptable.
What drawings are normally useful for a diesel bund submission?
Useful documents include the tank data sheet, site and layout plans, bund plans and sections, capacity calculations, fuel-system schematics, equipment schedules, structural details, and coordinated fire-safety and environmental information.
Does an outdoor bund need allowance for rainwater?
An outdoor bund may collect rainwater, so the design should state whether rainfall, freeboard, or other external inflows are included. The associated removal and isolation procedure should be defined as well.
Why do submissions receive comments even when the bund is large enough?
Capacity is only one part of compliance. Review comments may concern drainage, access, fire separation, ventilation, penetrations, emergency isolation, inconsistent tank data, or details that are missing from the drawings.
What should happen when the generator or tank is modified?
Review the approved arrangement before the modification is carried out. Changes to capacity, pipework, location, containment, drainage, or emergency controls may require updated drawings, calculations, records, or authority consultation.