How to Write an Industrial Door Technical Specification for a Tender

In a tender document, the job of the technical specification is not to describe the product but to make the bids comparable. A clause written without measurements (“quality panels shall be used”) is met differently in every bid, and at evaluation you are left with no comparable figure. A clause written with measurements both aligns the bids and becomes your acceptance criterion at delivery.

This article sets out how to build an industrial door specification, using the structure of our own product specifications. The reader in mind is the engineer preparing the tender, the technical buyer and the project office.

First, the most critical clause: certificate scope

An industrial door is not a product but a system: panel, hardware, springs, motor, control unit and safety equipment work together. Conformity to EN 13241-1 is likewise certified on that whole system, by testing the door in working order.

The trap here is this: tests carried out separately on the motor, the door hardware and the panel do not amount to a certificate for the door. Seeing three separate component certificates attached to a bid does not show the system has been certified. If your specification does not say so explicitly, two bids look identical on paper while one has passed a system test and the other has not.

The equivalent clauses in our own specification read:

• System test — the door shall hold a whole-system quality certificate, tested together with its motor and control system.

• Test condition — it shall be certified to EN 13241-1 on the basis of tests performed on the door in working order, including motor, control and safety systems.

• Definition of the tested motor — the characteristics of the motor used in the certification test (torque, speed, limit switch type, manual release arrangement) shall be stated.

• Rejection of separate tests — components having been tested individually does not substitute for a system certificate.

The eight headings of a specification

An industrial sectional door specification is built under these headings, and the order matters too, because evaluation follows it:

1. Certification requirements. The system test clauses above.

2. Panel characteristics. Infill density and type, panel thickness, sheet thickness, panel height options, surface pattern, standard RAL colour, performance classes.

3. Tracks. Track size and wall thickness, the safe-stop arrangement at the top, the connection between the return tracks, compatibility with the lift types.

4. Hinges and rollers. Material, noise behaviour, side capping profiles.

5. Torsion springs. Standard conformity, cycle life and its alternatives, spring-break safety, corrosion protection.

6. Cables. Construction (wire count and lay), tensile rating, cable-break safety.

7. Sealing. Top, bottom and inter-panel seals, the perimeter seal and its flexibility at low temperature.

8. Powered or manual operation. Manual opening during a power cut, the chain hoist option, pneumatic safety, locking arrangement.

How to write a measurable clause

The rule reduces to three parts: standard number + class + numerical value. Written together, the clause becomes auditable.

Examples, from our own specification:

• Panel: polyurethane infill at 40 kg/m³ between galvanised sheets, 40 mm panel thickness, 0.40 mm sheet thickness, panel height options of 460 / 500 / 560 / 610 mm.
• Wind resistance: EN 12424 Class 3 (700 Pa, that is 71.38 kg/m² or 0.109 kN/m²). Writing “Class 3” alone is not enough; the corresponding pressure should be stated too.
• Water tightness: EN 12425 Class 2. Air permeability: EN 12427.
• Sound insulation: R’w = 26 dB.
• Torsion springs: conformity to DIN 17223, 15,000 cycles as standard life, with 25,000, 50,000 and 100,000 cycle alternatives available on request.
• Cables: 6 × 19 = 114 wires laid around a polypropylene core, rated to 200 kg/mm²; cable-break safety as standard.
• Seals: the perimeter and head seal shall retain flexibility down to −30 °C.

The cycle life item deserves separate attention: the difference between 15,000 and 100,000 cycles is, at a facility running 40 cycles a day, the difference between roughly one year and seven. Where the specification does not state the expected cycle count, bids get priced with different spring lives and the cheapest bid is the shortest-lived one.

Five mistakes that make bids incomparable

1. Naming a brand or model. In public tenders this is usually prohibited anyway; in private projects it closes off competition. State the technical value that brand delivers rather than the brand.

2. Giving a class without its standard. “Class 3” on its own does not say which standard’s class it is; write EN 12424 Class 3.

3. Not stating certificate scope. The system-versus-component distinction above; this is the most expensive mistake, because it surfaces after delivery.

4. Omitting cycle life. Bids given without a stated usage intensity cannot be compared; the same door gets priced against different spring classes.

5. Leaving dimensions and lift type blank. Without the headroom, the lift type is assumed by whoever is bidding, and each bid prices a different installation.

Start from the ready specifications

Ready technical specifications for industrial sectional doors, high-speed PVC doors (roll and folding), dock levellers (hinged and telescopic) and dock shelters are on our Catalogues and Documents page, and the same files appear in the documents section of the relevant product pages. They are prepared bilingually, so the English section can be used directly on export projects.

Rather than copying them wholesale, we suggest selecting the items your project calls for: cycle life according to your usage intensity, insulation and sealing classes according to your environment, motor and safety equipment according to your traffic. Send us the dimensions and the usage profile and we can work out together which clauses actually govern your project.