An HCR module take-off should start with the approved module layout, then turn that layout into a traceable order schedule. Dividing the whole landscape area by a unit footprint can provide a rough check. It cannot confirm how many complete modules will fit around edges, drains or other features.
This guide is for buyers and site coordinators who already have a proposed HCR application. It explains how to separate a preliminary estimate from a quantity ready for supplier review. Hydraulic and structural design remain separate project decisions.
Start with the area that will actually receive modules
First, mark the module field on the latest drawing. Give each separate field a simple reference, such as Zone A or Zone B. Then identify the drawing number, revision and measurement units. These small details make the quantity easier to check when the layout changes.
A landscape boundary may include several areas that do not receive modules. For example, a plan might show a service zone, an access opening or a change in construction. Ask the designer to identify these areas clearly. Do not decide on site that a module can bridge an opening or be cut around it.
Also record unresolved boundaries. A provisional edge should remain visible in the take-off, with a named person responsible for confirming it. Otherwise, an estimate can become an order before anyone notices that part of the layout is still undecided.
Use the current HCR format for the first check
The current HCR stormwater storage module page identifies HCR-1000 as a factory-assembled unit measuring 1000 × 1440 mm in plan and 82 mm deep. Its nominal plan footprint is therefore 1.44 m². The depth describes the module itself; the complete construction needs space for its other layers.
For an HCR module take-off, use the confirmed product drawing as the dimensional reference. Keep the nominal footprint calculation beside the drawn unit count. If the two disagree, check the boundary, orientation and excluded areas before changing the order.
Quantity is not storage capacity. A footprint and module count do not establish usable water volume, discharge performance or allowable loading. Ask the project designer to confirm those matters using the relevant system information.
A simple quantity example, with its limits
Consider a hypothetical rectangular field measuring 10.0 × 14.4 m. If the approved layout places ten 1.0 m module widths across one direction and ten 1.44 m lengths across the other, it contains 100 complete units. The nominal area check gives the same result: 144 m² ÷ 1.44 m² = 100.
This is an arithmetic example, not a project design or a promise that any 144 m² area takes 100 modules. A narrow strip, an irregular boundary or an opening can produce a different layout. Rotating the units may also change how the field meets its edges.
Now suppose the example drawing changes. The revised layout contains only 96 complete positions, while a boundary detail awaits approval. Record 96 confirmed positions and describe the unresolved area separately. Do not turn the remaining area into an invented fraction of a module.
Build an order schedule that another person can follow
Use one line for each zone and product configuration. The following entries are a suggested working format, not a fixed HOENSOEY ordering requirement.
| Record | What to enter | Purpose |
|---|---|---|
| Layout reference | Zone, drawing number and revision | Links the count to an agreed plan |
| Confirmed quantity | Count of complete module positions | Separates counted units from area estimates |
| Open items | Unresolved edges, interfaces or configurations | Keeps assumptions visible |
| Delivery stage | Required zone and target delivery sequence | Connects procurement with site readiness |
Next, list any separately required items against their approved details. Do not assume that every project uses the same accessories or layer arrangement. Confirm the supply scope with the supplier before treating a schedule as complete.
Keep any requested spare units separate from the installed count. Agree the allowance for the particular project instead of adding an unexplained standard percentage. This lets the buyer see what is intended for installation and what is held for an agreed contingency.
Check revisions before releasing the order
Before ordering, compare the schedule with the latest issued drawing. Ask a second reviewer to follow the zone references and count the positions independently. Focus on changed boundaries and interfaces, where an old quantity is easiest to overlook.
Then record the change itself. A useful revision note says which zone changed, which drawing replaced the old one and how the quantity moved. “Updated quantity” alone leaves the next person without an explanation.
For staged deliveries, also reconcile the total approved quantity, the quantity already ordered and the balance still required. This prevents a revised total from being mistaken for a new additional order. Confirm packing and unloading arrangements against the actual delivery proposal; a module count alone does not establish container capacity.
Send a clear package for review
A useful HCR module take-off brings together the current layout, confirmed unit count, open questions and delivery sequence. It should make uncertainty easy to find instead of hiding it inside a single total.
For the earlier product-selection stage, see our stormwater module comparison checklist. When the layout is ready for supply review, contact HOENSOEY with the drawing revision, intended application, quantities and delivery destination.