Specification guides.

Specifying linear LED lighting well means fixing the details that decide how a scheme looks and performs long after handover: output and efficacy, optic and beam, glare rating, colour temperature and rendering, finishes, drivers and controls. These guides set out what to put on a specification, what to ask suppliers for, and where substitutions usually creep in. They are written by the 299 Lighting technical team from the questions architects, interior designers and M&E engineers ask us on live projects.

What these guides cover

• What to include in a linear LED lighting specification and schedule
• Performance data to request: photometry, UGR, CRI, lifetime and warranty
• How to protect the design intent at tender and value engineering

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All specification guides

• Direct vs direct/indirect linear lighting: which should you specify? — How direct and direct/indirect linear LED luminaires differ, and when to use each in offices, education and hospitality.
• UGR19 explained: glare control for linear office lighting — What the Unified Glare Rating means, why UGR19 is the benchmark for offices, and how linear luminaires are designed to meet it.
• CRI explained: why colour rendering matters in design-led interiors — What CRI (Ra) means for linear LED lighting, when to specify CRI 80 or CRI 90+, and why it matters for materials, finishes and people.
• How to read a linear LED datasheet — A plain-English guide to the numbers on a linear LED datasheet: lumens, watts, efficacy, CCT, CRI, UGR, IP rating, lifetime and dimming.
• Lumens per metre and efficacy: sizing linear lighting — How to use lumens per metre and lm/W efficacy to size and compare linear LED lighting for offices and commercial interiors.
• Microprismatic vs opal diffusers: which should you choose? — The difference between opal and microprismatic diffusers on linear LED lighting, and how each affects glare, efficiency and appearance.
• BIM, IES and LDT files: what specifiers need from a lighting supplier — Which digital files architects and lighting designers need for linear LED lighting: BIM objects, IES and LDT photometric files, and datasheets.
• LED lifetime explained: L70, L80 and maintenance — What L70, L80 and B-values mean for linear LED luminaire lifetime, and how to plan maintenance for commercial lighting.