Q: How many emergency lights do I need?

It is the greater of two checks: the lumen method (zone area × required lux ÷ maintenance factor ÷ luminaire output) and the spacing rule (luminaires no further apart than ~4× the mounting height on escape routes). BS 5266-1 also requires a luminaire within 2 m of each exit, change of direction, stairway and fire-fighting point.

Q: What lux level is required for emergency lighting?

BS 5266-1 requires a minimum of 1 lux along the centre line of an escape route , 0.5 lux in open (anti-panic) areas excluding a 0.5 m border, and 15 lux (or 10% of normal) in high-risk task areas.

Q: How long must emergency lighting stay on?

A minimum of 3 hours for sleeping-risk premises, places of assembly, and where the building may be reoccupied without waiting for battery recharge; 1 hour may be acceptable for premises evacuated immediately and not reoccupied. Most modern installations use 3 hours.

Q: What is the difference between maintained and non-maintained?

Maintained (M) emergency luminaires are lit at all times (used where the area is occupied in darkness, e.g. cinemas). Non-maintained (NM) luminaires only illuminate when the normal supply fails — the most common type for offices and circulation routes.

Question 1

How many emergency lights do I need?

Accepted Answer

It is the greater of two checks: the lumen method (zone area × required lux ÷ maintenance factor ÷ luminaire output) and the spacing rule (luminaires no further apart than ~4× the mounting height on escape routes). BS 5266-1 also requires a luminaire within 2 m of each exit, change of direction, stairway and fire-fighting point.

Question 2

What lux level is required for emergency lighting?

Accepted Answer

BS 5266-1 requires a minimum of 1 lux along the centre line of an escape route, 0.5 lux in open (anti-panic) areas excluding a 0.5 m border, and 15 lux (or 10% of normal) in high-risk task areas.

Question 3

How long must emergency lighting stay on?

Accepted Answer

A minimum of 3 hours for sleeping-risk premises, places of assembly, and where the building may be reoccupied without waiting for battery recharge; 1 hour may be acceptable for premises evacuated immediately and not reoccupied. Most modern installations use 3 hours.

Question 4

What is the difference between maintained and non-maintained?

Accepted Answer

Maintained (M) emergency luminaires are lit at all times (used where the area is occupied in darkness, e.g. cinemas). Non-maintained (NM) luminaires only illuminate when the normal supply fails — the most common type for offices and circulation routes.

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