Specification guides.

Specifying recessed 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 recessed 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

• Multi-optic recessed downlights explained — Multi-optic recessed downlights such as Foss group several small, individually shielded LED optics in one housing, giving high output, very low glare and precise beams.
• Glare and UGR in recessed lighting — Recessed lighting glare is measured using UGR; aim for UGR 19 or lower in offices and classrooms by choosing well-shielded optics and confirming with room calculations.
• Downlight beam angles explained — Beam angle controls how widely a downlight spreads light: narrow beams accent, medium beams suit general light in higher ceilings, and wide beams give even coverage.
• IP ratings for recessed downlights explained — IP ratings describe protection against dust and water; recessed downlights in bathrooms, kitchens and other damp areas need a rating suited to their location and zone.
• Choosing colour temperature for recessed lighting — Most commercial recessed lighting uses 3000K to 4000K; warmer 2700K to 3000K suits hospitality, while 4000K suits offices and education.
• Colour rendering (CRI) in recessed lighting — CRI measures how accurately light shows colours; specify CRI 80 for general areas and CRI 90+ for retail, hospitality, galleries and client-facing spaces.