Lighting Calculation as Per AS 2293

0.2 lux is basically darkness....so I don't think you are correct using that as a minimum...

..."The key parameters for emergency lighting as defined in NFPA 101 are the requirements for stairs to have a minimum of 10 fc (108 lux) measured at the walking surface, and a minimum of 1.0 fc (10.8 lux) for floors and walking surfaces with an exception for assembly occupancies of 0.2 fc (2.2 lux) during periods of performances or projections involving directed light (a movie theater).

In the event of a power outage, the emergency lighting must be transferred to its alternate source within 10 sec. Additionally, battery-powered emergency lighting shall be continuously available for 1.5 hours after the power outage. The emergency illumination shall be spaced to provide initial illumination along the defined path of egress of not less than an average of 1.0 fc (10.8 lux) and not less than 0.1 fc (1.1 lux) at the floor of the defined pathway. At the end of 1.5 hours, the illumination levels are permitted to decline along the path of egress as the emergency power source discharges to an average of 0.6 fc (6.5 lux) but not less than 0.06 fc (0.65 lux). In order to provide sufficient contrast and subsequent visual acuity, the maximum to minimum illumination uniformity ratio shall be no greater than 40:1."...

Can't be that much difference between codes I would think....crikey

https://www.csemag.com/articles/the-basics-of-emergency-illumination/

My WAG is that it should depend greatly on the type of area one is evacuating from. A warehouse will have very different evacuation illumination concerns than any biosafety level areas.

(Yes, I am using hyperbole to make a point.)

Complete area makes some sense when you think about it. Our joint standard AS/NZS 2293.1:2005 (the older version I have referenced here) calls for 1 lux in exitways and at every change in level in an escape route, and 0.2 lux everywhere else.

0.2 lux was chosen as it is enough light to navigate by to get to the lit exits. Not really an issue in small areas or areas with open floor plans where the exit and escape route lighting is providing enough spill but in larger areas or where the floor plan blocks the light that could result in issues.

Do the calculations, you may find that the exit/escape route lighting provides enough light to meet the 0.2 lux criteria just by spill alone. If not then add a few extra lights to fill out the lighting pattern.

@jack of all trades : I agree with your reply as i have read AS/NZS 2293.

But in my project almost all rooms (or areas) have lot of equipment installed which is blocking light.Its an industrial plant so lot of operating platforms.

Anyways my query is that in that case we dont have to design any evacuation route because we have to calculate lux over whole area.

Normally we calculate over escape routes and centre line as per european standard (EN1838).But in AS 2293 nothing is mentioned like that.

You will likely need to design using common sense and add some derating factors, adding extra lights to areas and estimating or calculating that enough light will reflect and spill into all the areas.

Remember, light will reflect of all surfaces to some degree filling a crowded room and 0.2 Lux is not a large value.

For example do a basic assessment of what type of equipment is going in and potentially blocking the light and then apply a derating factor to an empty room calculation (0.2 Lux is only the minimum value, you don't have to worry as much about light level uniformity).

For large room blockages section the room up into multiple areas and treat them as independently lit rooms.

I do not have the Australian standard. I have designed & installed emergency lights for church centre in UK.

Is any safety officer/jurisdiction going to approve a plant where an escape route requires scrambling over machinery??

With normal lighting there are strict requirements over what constitutes an escape route for width & lack of obstructions.

My contract engineer's hat asks - did your quote write that your design was for 0.2 lux on escape routes only?? Did customer's spec clearly require 0.2 lux on whole area or define escape routes??

Have all tenderers quoted for whole area? - else the assessment process is not fair.

I can see that, if personnel could be working in the middle of machinery when lights fail, then light should be enough to avoid mashing a knee on projecting bits. If customer requires overall lighting, that is fine, so long as he pays a fair price for it.

I used the IEEE "Electrician's Guide to Emergency Lighting". This specifies 1 lux min at floor centreline on 2m wide escape routes, with a departure from Euro standard permitting 0.2 lux on unobstructed escape routes for UK.

This clearly divides requirements into escape routes & "open area where escape routes are ill defined such as halls or premises over 60 sq.metre area". An obvious example is where seating means there must be enough light to avoid seats while leaving - open area light is also described as "anti-panic" [shades of current virus Panpanic!]. Lighting for open areas required 0.5 lux minimum at floor, except for 0.5 metre border on perimeter. This is all with zero reflection surfaces, else there would be endless "weasel wording" & dispute about reflections [folk can always paint the wall from white to black later, not knowing why it was white].

An 0.2 lux general open area requirement does not seem very onerous compared to this or other standards mentioned in this thread.

The following picture is what the DIALUX computer program plots for the 86 sq.metre hall with two lamps. The red lines are 2 lux while the green line at the 0.5m border is 0.5 lux, except tiny bits at top corners.