Overview
ISO/CIE TS 22012:2019 - "Light and lighting - Maintenance factor determination - Way of working" specifies a standardized way of working for determining the maintenance factor for indoor and outdoor lighting installations. It adapts the established CIE methodology (CIE 154:2003 and CIE 097:2005) and integrates IEC product-performance data to address modern technologies such as LED luminaires, including features like CLO (constant light output) and LED useful-life metrics.
Key topics and technical requirements
The technical specification defines the scope, terminology and a step‑by‑step method for calculating the maintenance factor used in lighting design and verification. Major topics include:
- Influencing factors: luminaire/light‑source characteristics, recoverable (e.g., dirt on luminaires) and non‑recoverable external factors.
- Luminous flux factor (fLF): accounting for gradual light‑output depreciation over time (including CLO cases).
- Survival factor (fS): treatment of catastrophic failures, with guidance for spot, group, or combined replacement regimes.
- Luminaire maintenance factor (fLM) and surface maintenance factor (fSM): guidance for indoor and outdoor luminaires and for room/area surface refurbishment.
- Maintenance period and intervals: cleaning, component replacement and surface refurbishment planning.
- Use and documentation: how to apply the maintenance factor in lighting design, verification and record‑keeping.
- Definitions and symbols for LED-specific parameters (e.g., median useful life Lx, abrupt failure value AFV, failure/survival probabilities).
Practical applications
ISO/CIE TS 22012:2019 is practical for:
- Producing robust lighting designs that maintain required illuminance levels over time.
- Preparing specifications and procurement documentation that reflect realistic maintenance and performance expectations.
- Developing maintenance schedules (cleaning, component replacement, surface refurbishment) to meet design targets.
- Performing post‑installation verification and lighting audits, including energy compliance checks.
- Assessing life‑cycle performance of LED installations where long lifetimes, low failure rates and CLO functionality affect depreciation and replacement strategies.
Keywords: maintenance factor, lighting maintenance, luminous flux depreciation, LED maintenance, luminaires, survival factor, CLO, lighting design, outdoor lighting, indoor lighting.
Who should use this standard
- Lighting designers and illuminance engineers
- Facility managers and maintenance teams
- Municipalities and highway lighting authorities
- Lighting product manufacturers and specifiers
- Energy auditors and sustainability consultants
Related standards
The specification references and builds on:
- CIE 154:2003 (outdoor maintenance)
- CIE 097:2005 (indoor maintenance)
- IEC 62722-2-1 and IEC 62717 (LED luminaire and module performance)
ISO/CIE TS 22012:2019 helps translate established CIE methods into a clear, LED‑aware way of working so designers and asset owners can plan reliable, energy‑efficient lighting that performs as intended over its service life.