Daylighting roof panels: reducing lighting energy in textile factories

Archived article about daylighting and products at the time of publication. Quoted savings, productivity improvements, illuminance, payback, standards and warranties are historical claims, not universal guarantees or current specifications. Assess the actual task, product, maintenance needs and site conditions.

Opportunities to reduce lighting electricity

Lighting was estimated to represent around 40% of electricity consumption in the textile and garment facilities discussed. Reducing lighting electricity while maintaining or improving lighting quality was therefore presented as a major opportunity for garment factories.

Earlier measures included replacing fluorescent lamps with T8 (2 x 36 W) and T5 (2 x 28 W) systems throughout workshops. Daylighting roof panels offered another option, with relatively low investment and potential lighting-electricity savings of up to 70%. These figures depend on the building and operating conditions.

Lighting quality and daylighting design

Appropriate lighting in production rooms and workplaces supports working conditions, safety, productivity and product quality. Adequate illumination and suitable light colour were associated with a 20–30% productivity improvement in the cases discussed. Inadequate lighting can contribute to eye fatigue and accident risks. A range of 300–500 lux was used as an example for workshops. Lighting design should be assessed for the actual tasks rather than treating that range or the quoted improvement as a universal requirement or guarantee. A daylighting system uses windows or translucent panels in the roof and/or walls to admit natural light and reduce daytime artificial-lighting demand.

Products and project examples

Daylighting-panel suppliers included Ampelite of Australia, distributed by Fianh. Customers included Seiko, Posco, Zamil, Shimizu and Dong Son among construction companies or contractors using the products, and Esquel and Tinh Loi garment factories among the cited projects.

The panels can be considered for new factories and for suitable existing roofs to make better use of natural light.

Product specifications and claims at the time

Product specifications included AS/NZS 4256 Parts 1 and 3:1994 and an AS/NZS ISO 9002 quality-management process. Fianh Ampelite FRP Skylight was promoted with the following features: lower costs, payback of 1-3 years, no maintenance, low weight and easy installation, durable materials, and a warranty of up to 20 years. Performance claims included heat-transmission reduction exceeding 70% and light transmission above 70%. Daylighting can reduce reliance on electric lighting and associated electrical risks. These historical product claims are not a current specification or warranty; suitability, maintenance and actual savings must be checked for the selected product and site.

Applications and assessing actual performance

Possible applications included production and assembly workshops, warehouses, textile and garment factories, public buildings, shopping centres and homes. Daylighting could reduce lighting electricity, the required number and size of windows, operating costs and environmental impacts. Some projects reported reductions of up to 80%. Actual outcomes depend on daylight availability, building design and lighting controls.

The supplier emphasised raw-material quality, manufacturing technology, product quality and customer service, and reported use by customers worldwide, particularly textile and garment companies.

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