Specification guides.

Specifying suspended 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 suspended 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 pendants: which to specify — Direct pendants send all light downward for efficiency and drama, while direct/indirect pendants also light the ceiling for softer, more comfortable rooms that help meet LG7.
• How high should suspended lighting hang? — Pendant height depends on ceiling height, task and distribution; office linear pendants usually hang well above head height, with direct/indirect fittings needing enough gap to light the ceiling.
• Glare and UGR with suspended lighting — Suspended lighting glare depends on optics, brightness and drop height; aim for UGR 19 or lower in offices and confirm with a room calculation.
• Spacing and layout for linear pendants — Pendant spacing depends on output, distribution, drop height and target illuminance; plan rows parallel to windows and desks and confirm with a lighting calculation.
• Colour temperature for pendant lighting — Use 2700K to 3000K pendants for hospitality and homes, 3000K to 3500K for retail and receptions, and 3500K to 4000K for offices and education.
• Colour rendering for pendant lighting — Specify CRI 80 for general office pendants and CRI 90+ for retail, hospitality and client-facing spaces where colour accuracy matters.
• High-output pendants for large volumes — High-output suspended linear such as Arno lights large volumes, high ceilings and industrial spaces efficiently with fewer fittings.