Shop drawings, mock-ups and approval for bespoke lighting

At a glance

Not every piece needs every stage. The stages are practice, not a standard: agree your own split with the workshop.

Six stages, and what each signature locks

Not every light needs every stage. A plain pendant in a standard finish may need only a shop drawing and a finish sample. A large, heavy, repeated or dimmable fitting often needs all six. What matters is that each signature is for something specific. “Approved” on a drawing says the sizes and the arrangement are right: it does not say the glass is the right colour, or that the light is right at 10 per cent. The drawing shows the order the stages usually come in, and what each one locks.

This sheet is the lighting version of three general sheets: sample hierarchy and approval (seven kinds of sample), the shop drawing approval checklist (twelve checks on a drawing) and prototype and mock-up approval (the general rules for a prototype or a mock-up room). They apply here too. What lighting adds is weight and fixings, the electrical arrangement and its compliance, and the light itself.

What each signature locks

A filled dot in the matrix means the signature at that stage is the one that binds the attribute: after it, a change is a revision. A ring means the stage shows or checks the attribute without binding it. The marks are our judgement of a sensible split, not a standard, so agree your own with the workshop at the start and write it into the approval note.

Two things follow from the matrix. First, size, weight and IP rating are fixed on paper, so the shop drawing is where the electrical engineer and, for a heavy fitting, the structural engineer have to look. Second, the light itself, lamp, colour temperature, driver and dimming, is fixed last and only by looking, which is why the lit mock-up cannot be replaced by a drawing or a data sheet.

What a lighting shop drawing shows that a cabinet drawing does not

The shop drawing checklist covers any piece of furniture or joinery: title block, datum, overall sizes, material, finish, hardware, fixings, services, tolerances, access and notes. A luminaire needs those and the following, which a cabinet does not.

• Suspension and fixing. Canopy size and ceiling build-up, the type of fixing, the load it carries, the drop and whether it adjusts, and how the fitting is levelled and locked off.
• Weight. Total weight as built, glass included, and the load on each fixing. The structural engineer needs it. This sheet gives no weights and no load figures.
• Electrical arrangement. The supply, the cable and gland, the lamp holder type, the light source type and its maximum power, the driver type and where it sits, how it is reached for replacement, and the heat clearances.
• The light. The light source, its colour temperature and colour rendering, and the dimming protocol the driver accepts: see the dimming protocols sheet.
• Compliance and marking. The IP rating, the protection class, where the rating plate sits, and the declaration of conformity that will come with the fitting: see the IP and IK ratings sheet.
• Glass and fragile parts. How each glass element is held, which parts are replaceable, and how many spares are supplied.
• Access and installation. The re-lamping and cleaning route, assembly on site and packing: see the packing and installing sheet.
• Revision letter and date, the sample references the drawing relies on, and a note of what is not yet fixed.

A drawing is only one of the documents. This table shows which one answers which question, so nobody signs a drawing to approve the light:

Glass and finish samples: approve them lit as well as unlit

Glass and finishes are approved on the real material, in a named light, and the signed sample is kept as the control sample: see the sample hierarchy sheet. Three lighting points are added.

• Look at glass unlit, lit and dimmed. The same glass reads differently with a lamp behind it, and again when the lamp is dimmed. Approve it in the state you mean, or in all three: the Murano glass colour sheet sets this out.
• Agree the range, not only the sample. Handmade glass varies between pieces. The acceptance criteria sheet shows how to agree what is acceptable before the first piece is made.
• Metal on the same metal. A plated or patinated finish is approved on the same base metal and process, with the batch variation noted: see the metal finish sample sheet.

How samples and prototypes are handled, and who bears them, is agreed with the commission before they are made, as on our sampling page. Nothing on this sheet promises free or on-demand samples.

The lit mock-up: how to run it

A lit mock-up answers the question no drawing can: what this fitting does to this room, with this lamp, at this hour. The US Department of Energy report on dimming LEDs with phase-cut dimmers (PNNL-22945, October 2013, updated August 2014) recommends a full mock-up of every lighting circuit, including all the LED sources and the dimming controls, tested over the whole dimming range. Its reason is that compatibility alone does not guarantee smooth dimming, absence of flicker or a usable lowest level: those are best judged by looking. The report is about US phase-cut dimmers and UK controls differ, but the reasoning carries over to any dimmed fitting.

How to run one:

1. Use the real components. The specified light source, the specified driver and the specified dimmer or control. The report says to procure enough of the specific sources to simulate the expected maximum and minimum loading of the circuit, then raise and lower the level.
2. Step through the whole range in levels you write down, and look at the lowest level, the smoothness of the dimming and any flicker. If the behaviour is not acceptable, the report suggests switching the dimmer to a different load type, where it has one, and testing again.
3. Hang it where it will hang: at the real height, over the real table, bar or bed, with the real materials around it. A US lighting practice notes that laminates, veneers, glass and acrylics behave unpredictably with light, which is why they are tested lit.
4. View it at the hour of use, with the room’s other lights and any daylight as they will be, from the places people will sit and stand: see the pendants sheet and the lighting levels sheet.
5. Compare fittings side by side if there will be several: one sample cannot show the spread in colour and brightness between pieces. The colour temperature sheet explains why dimmed colour is worth checking.
6. Record it: source, driver, control and settings, the levels tried, who attended, photographs with the conditions noted, and the decision, on the approval record below.

What a mock-up does not prove

It does not prove that the ceiling can carry the load, that the fitting conforms to the electrical rules, or that the finish will hold across a full run. Those belong to the structural engineer, the declaration of conformity and the control sample. Time and change also matter: the report warns that products can change between ordering and delivery, and that any substitution of a lamp, driver or dimmer needs the compatibility checked again and documented.

An approval record you can copy

Use one record per stage and item, signed and dated, and file it with the drawing it refers to. The fields below work for every stage.

After approval: what counts as a change

After release for making, the signed set is the benchmark. These changes are new revisions that need a new signature, and sometimes a new look at the mock-up:

• A different light source, colour temperature, driver or dimmer, even a nominally equivalent one.
• A new batch of glass or a different glass supplier, or a new finish batch, outside the range agreed.
• A change to size, drop, weight, fixing or canopy.
• A change to the diffuser, shade or any part that alters how the light leaves the fitting.
• A delay long enough for the products to change: check the specified components again before purchase.

The first piece and the delivery check are then made against the signed set: the control samples, the drawing revision and the mock-up record.

Before manufacture the supplier issues shop drawings of each luminaire type for approval, in plan, elevation and section, to dimension, showing overall size and drop [ ], total weight [ ] kg and the load on each fixing, canopy and ceiling build-up, fixing detail, electrical supply, driver type and position with access, light source type and maximum power, IP rating, protection class and rating plate position, glass fixings and spares. Each drawing carries a revision letter. Nothing is made until its drawing is returned approved, or approved as noted.

Glass and finish samples are made on the specified material, reference [S-01] and [S-02], and approved in [named light] unlit, lit at full output and dimmed to [ ] per cent. The approved sample is the control sample: one copy is kept by the designer and a matching copy by the supplier. The range of variation accepted in production is [as agreed in writing].

A full-size prototype of luminaire type [L-04] is made as drawing revision [C], weighed, and presented at [location] for approval before the production run. [Applies to the types marked P on the luminaire schedule.]

A lit mock-up of luminaire type [L-04] is hung at [location] with the specified light source [make, model, [2700] K], the specified driver [make, model] and the specified dimmer or control [make, model], on a circuit loaded as in the design. The dimming range is tested in [steps] steps from [lowest level] to full output at [time of day], recorded on the approval record, and approved in writing. Any later change of light source, driver or control re-opens the mock-up.

A change to any approved item after sign-off, including light source, driver, dimmer, glass or finish batch, size, weight or fixing, is made as a new revision and signed again before the affected items are made.

Standards and sources

• US DOE and PNNL: Dimming LEDs with Phase-Cut Dimmers, the Specifier's Process (PNNL-22945, Oct 2013, updated Aug 2014): section 3.1.2 read 5 Nov 2026; US phase-cut context.
• A US lighting design practice: The Role of Lighting Mock-Ups (J. Widmer, undated): backlit materials; no dimming.
• Hotel-industry trade press: sample rooms (18 Feb 2026) and bespoke lighting (10 Mar 2021): context only; no figures used.
• Make Bespoke Studio: Sampling: two sampling moments; mock-ups and prototypes for complex or high-value commissions.

Questions we are asked

What is a shop drawing for a bespoke light?

It is the maker's detailed drawing of the fitting as it will be made and fixed, issued for approval before manufacture. For a luminaire it shows sizes and drop, weight and fixing load, the ceiling build-up, the electrical arrangement, the driver position, the IP rating and the glass fixings, at a stated revision. It does not show how the glass or the light will look: samples and a mock-up do.

Is a prototype the same as a mock-up?

Makers and designers use the words differently, so say which you mean. In this sheet a prototype is a full-size piece built as drawn, to judge proportion, build and weight, and a lit mock-up is a fitting hung in position with the real lamp, driver and dimmer, to judge the light. One piece can serve as both if it is built and lit in position.

Does every bespoke light need a lit mock-up?

No source we read says so. A mock-up earns its place when the light matters: a dimmed fitting, a repeated fitting, a large or high-value piece, or one that is hard to change once hung. A plain fitting in a standard finish may need only a drawing and a sample. Agree it in the scope.

What should a lit mock-up test?

The lamp and its colour temperature, the driver and dimmer working together across the whole dimming range, the lowest level, flicker, glare from where people sit and stand, and how the glass and finishes look lit at the hour of use. The US DOE report recommends testing every lighting circuit with its real LED sources and controls over the full range.

Who pays for a prototype or a mock-up?

That is agreed in the scope and the quotation before it is made. We give no figure here, and no partner workshop's terms have been checked for this sheet.

Can the lamp or driver change after the mock-up?

Only as a new revision. The DOE report says that any substitution of a lamp, driver or dimmer needs the compatibility checked again and documented, because a change can alter the dimming behaviour or the load the dimmer can handle.

What is the difference between approved and approved as noted?

Approved releases the item for manufacture as drawn. Approved as noted means correct the noted points first, then release. See the shop drawing approval checklist for the four outcomes of a drawing review.