I'm running an emergency lighting calculation and I am puzzled by necessity to include the results of an invisible grid in brackets, I can understand that they are results which are based on a fine grid and will often provide more accurate results although this fine grid is not view-able or adjustable, I cannot find any part of EN12464 that insists on the grid being below 0.5m and the inclusion of this increases the calculation time. Is there any way to turn the calculation of the fine grid off or at least view the fine grid so I know the location of the shortfall in illlumiance?
On the topic of emergency lighting, could someone explain how the 'Boundary Line' results are calculated.
Are the results calculated right up to the boundary wall of the room, ignoring the 0.5m boundary zone?
Dear Stuart Challenger
Your entire measurement area is part of the calculation and the result.In many cases this is no problem, for example if you duplicate your evaluation area
and change it into an emergency area, usually you will already have a distance of 0.5m between this surface and the wall.
If you create your emergency area using the poygon tool, remember to keep a distance of 0.5m from the wall.
Relux Informatik AG
Dear Bernard Glossop
Perhaps we are now mixing too many different topics together so that it would be time to repeat and clarify the most important facts.
-ReluxDesktop uses always a very fine grid to calculate the emergency area. The result is displayed as pseudocolors.
-In order to create the result table, fewer measuring points are visible. But only because of the fact that there is not enough space to show all of them.
-If you create a emergency surface, you should add a distance of 0.5 meters to the border.
-The illuminance level should not be less than 0.5 lux within one metre and not less than 1 lux along the centre line of your corridor.
Relux Informatik AG
I have omitted my previous comment leaving your further clarification as, yes, I may have confused things. Apologies!
so I think you've covered most points here and thank you for the clarification, however; my problem with this fine grid (and as raised in an earlier post) is the calculation time required.
I'm currently working on several warehouses, generally 350m long by 180m wide, and having three or four floors with differing ceiling and mounting heights.
The last calculation I ran seemed to spend 3-4 hours on the emergency calculation alone, which is making delivering designs to deadline difficult.
Would it be possible to have a checkbox system for whether this fine grid is used, and perhaps have a 'disclaimer' that automatically appears on the results page if it is turned off?
Perhaps something like "the designer has switched off the fine measurement grid feature for this measuring plane, and takes professional responsibillity for the results herein.".
I would suggest this is done on a plane by plane basis, as some smaller measuring planes would benefit from the fine grid, but the whole floor emergency plane could be done without the fine grid, hopefully saving calculation time.
Thoughts and comments are welcomed.
Once 'off', always 'off'!
Dear Robert Stone
I can understand your wish for a faster calculation, but we need to make a fine-grid calculation to check if the results comply with the standards.
For the escape route as an example, we have to prove that the measuing surface has not less than 1 lux along the center line. Therefore ReluxDesktop has to place the measuing points very close to each other.
Without the fine grid, ReluxDesktop can no longer calculate the relevant results.
If the calculation takes too long, please check if your project contains too much information and if unnecessary objects can be removed.
We can also offer you to analyze your project and to give you some suggestions on how you can reduce the calculation time.
Relux Informatik AG
Thank you for the reply Basile.
Unfortunately I can't share my work, and there are times when the objects within the spaces are a necessary part of the contract design.
I guess I just have to be better at alotting time to design revisions.
"we need to make a fine-grid calculation to check if the results comply with the standards." - Why? What part of what standard states that the measurement points need to be a certain distance apart?
It's mainly for large open area calculations using objects that I find this to be an issue, not very small escape routes as you have demonstrated.
I understand that many projects benefit from this feature, although there are also a lot of projects that are hindered by it, hence the multiple requests to have it as an option rather than a necessity.
Dear Luke Harrington
In fact, if the firepolice measures with the luxmeter whether there is enough light on the floor during an emergency, they will probably go to the darkest place in the room and check whether there is enough light or not.
Relux needs to calculate many points to find the darkest area. What you can do is to create smaler measuring areas only at those places where you are sure that these areas will have the least amount of light.
Instead of calculating the entire corridor, you can place a measuring surface between two luminaires, and if the distance between the luminaire is always the same, no additional measuring surface is required.
Same applies to a larger open area calculation.
Relux Informatik AG
This is an interesting article on the realities of emergency illumination It’s an emergency – so why can’t I see where I’m going? Emergency illumination levels are rarely checked in real life (in the UK in my experience unless there is an obvious problem), although emergency lighting systems/luminaires are regularly inspected and tested.
"In fact, if the firepolice measures with the luxmeter whether there is enough light on the floor during an emergency, they will probably go to the darkest place in the room and check whether there is enough light or not."
Do they also wait until the maintenance factor is down to the designed level and temporarily paint to walls to a 0% reflectance value and place the measuring point of the light meter at exactly 0.00m?
A competent designer will always use sensible measuring grid spacings, and I do not feel we need the lighting design program to dictate how far apart they 'need' to be.