This is a specification that was produced recently for a specific project using various case sizes with internal fibre-optic lighting. However much of the specification can be used for other internal lighting system. For instance other types of light boxes still need safe access and through ventilation. Please feel free to copy, adapt and use the specification on your own jobs. Note that it is for you to determine if the specification meets your own project’s needs and we cannot be held responsible for any subsequent actions or results from using this specification. Contact us if you need specific advice on its use, adaptation or applicability.

Please let us know if there are points you would like to make about it or feedback from suppliers that may be useful to us or to others that use the specification in the future.

Case specification for internal fibre-optic system.

1. General

The fibre-optic lighting system is to be designed and installed in such a way as to allow safe and easy access to components for setting up and adjusting the lighting within the case.

2. Projector control

Tungsten-halogen projectors shall use dimmable high-frequency transformers and be supplied with a local dimmer control adjacent to it unless noted otherwise in the case schedule. Metal-halide projectors shall be provided with a mechanical disk type dimmer wheel, with adjusting control readily accessible from the outside of the projector.

3. Harness

The fibres in all harnesses shall be fully randomised at the common-end to ensure even light distribution over all tails.

4. Optics

In all cases adjustable optics shall be readily accessible for aiming and adjustment. The optics shall be adjustable to at least 35° from the central position in any direction and shall stay in position once aimed. The mounting of the lenses on the adjustable optics shall be such that they can be removed or interchanged between optics and be adjusted in or out to give some fine control of beam angle. Unless noted otherwise in the case schedule half the optics shall be supplied with medium angle (13mm/ ½” lenses) lenses and the other half with narrow beam (25mm 1”) lenses. 

5. System sizing

Unless noted otherwise in the case schedule the fibre-optic system is to achieve a lighting level of 200 Lux on the front surfaces of all objects and label panels in each case. The projector lamp size and tail sizes shall be chosen and supplied such that this lighting level, or that shown on the case schedule, can be achieved. See designer’s drawings for intended object and label layout.

6. Housing

Except where noted in the case schedule the projectors are to be housed in the top compartment of the case. Access panels on the projector compartment shall give clear access to the projectors for re-lamping or maintenance. To ensure safety any upward opening lids are to have integral latches or props to hold the lid safely in the open position.

7. Ventilation

Each projector compartment is to have low-level and high-level vents to allow through ventilation to avoid excessive heat build up that may affect the objects below and lead to shorter lamp life. All vents are to be light trapped to avoid light leakage from the compartment.

Lighting Design & Technology 2004. www.ldandt.co.uk. 01225 310022.