Home / Terms / Maintenance Factor Technical meaning Maintenance factor is an allowance for light loss between initial installation and the maintained condition used for the estimate. MF can include lamp or LED lumen depreciation, luminaire dirt, room surface dirt and the cleaning or replacement interval assumed for the project. Calculation use In maintained-light calculations, required lumens increase as MF decreases: required lumens = target lux x area / (UF x MF). MF is paired with UF so the result represents maintained light rather than an initial clean-installation condition. Not the same as MF is not a universal safety margin. It needs the environment, luminaire data and maintenance plan behind it. MF is not utilisation factor. MF describes depreciation and maintenance conditions; UF describes delivery to the assessed plane. Australian context Australian workplace and room records should avoid presenting MF as a hidden standard value; record the assumption and why it was selected. Examples Example Value Planning note Clean maintained interior MF 0.90 Needs maintenance evidence before relying on it in a formal record. Preliminary interior estimate MF 0.80 Typical calculator sensitivity value for controlled spaces. Dusty or uncertain condition MF 0.70 Raises required lumens and should prompt a maintenance-condition note.
Calculation limits and records Maintenance-factor rows are explanatory assumptions. Formal maintained-lighting design needs the applicable Australian source method, fitting data and maintenance evidence.