5.2.8.5 Toilet facilities and changing rooms

When posting on a forum where many users are electricians rather than engineers you need to consider how electricians think and work.

As an electrician I will choose emergency lighting supplied by manufacturers who provide spacing charts and diagrams that show you that if the ceiling height is X then the distance between the lights needs to be no more than Y, rather than doing calculations.

One manufacturers design team said they would check my design for one job by running through their lighting design software, I sent them sketches of each stairway, hallway and landing broken down into sections indicating the turns, they said it was too complicated and “it will be obvious anyway if there’s a problem from just walking through it after it’s finished “. 

So I’m unsure about the column headed “calculation required“ because I would generally just check the ceiling height and floor area to be illuminated on every job using a manufacturers spacing chart. 

The problem from my point of view is that many emergency lighting manufacturers just aren’t supplying the spacing charts and diagrams anymore, there seems to be an assumption that designers will use design software packages rather than just looking at some charts, even for something as simple as a few lights in a cafe or restaurant.

I remember talking to a forum member at Elex a few years ago, she said you have to be careful using designs by lighting designers who have used design software, because some of them “lower the ceiling height “ if they cannot get it to work as it should and you may not realise until the job is finished.

Sparkingchip: 
 

When I installed emergency lighting in a pubs toilet with two cubicles I simply placed the light above the intersection of the partitions so it throws light down into all three areas.

Surely from a practical point of view, if it is a circular light fitting over the intersection of the partitions the partitions no longer exist? 

I have issues with the concept of borrowed light and toilet cubicles, with some light shining into a toilet cubicle above both the door and possibly the partitions the door handle will be in a shadow and may not be easy to see, in amongst other things.

I think there is more than one problem when folk use software without actually understanding or in some cases even thinking about the problem - there is a tendency to believe the machine, when all it does is produce outputs that given enough time you could have done with a calculator - if you knew and understood the formulae the programmer used.  

But transposed digits or an incorrect assumption about partition positions or room sizes may lead to a silly answer. Using software to give you a more exact polished answer when you already know what sort of magnitude to expect is fine, but you need to know enough that when it says you need 100mm2 cable and lights every 15mm apart that maybe it is a case of "rubbish in - rubbish out" before automatically ordering the materials.

A non electric  example - a height of ‘six-two’  meaning six foot two, not 6.2cm  is processed by an unthinking computer and told his BMI is dangerous . Funny in that case, and luckily obvious, but it shows a worrying lack of error checking in the code and the wider process  that nothing and nobody said ‘that’s silly, no-one is that small…'

Mike.

The issue I have with “Borrowed light” is this:

Around fifteen to twenty years ago there was Guidance published by what I guess back the was the Office of the Deputy Prime Minister before it became the DCLG, then the MHCLG regarding borrowed light.

The example given was that if a block of flats had a stairwell with full height windows and a street lighting column outside then emergency lighting may not have been required, because the street lighting column would illuminate the stairs and landings whilst the internal lighting was not functioning.

I am sure you can see flaws in the idea that you could rely on a street lighting column outside of the building, but it was there in official guidance that was frequently referred to by Local Authorities and others.

I went and did the NAPIT Emergency lighting course back in September 2008 and we discussed this idea, then ripped it apart and discounted it as a practical solution.

So now I really question any suggestion of borrowed light for emergency lighting purposes, there's a building I have worked in that has a full height internal window between two stairways in a divided building with each half in separate ownership. The owner of the side of the building I was working in wanted to rely on next doors emergency lights shining through the internal window if there was a power cut, I am sure you can see the flaws in that plan as well.

Back to the topic, I am not convinced that the concept of borrowed light in toilet cubicles with doors and partitions around the stall that allow a small amount of light to shine into the cubicles above and below them is a workable solution, the emergency lighting in the cubicle is not expected to allow the user to be able to carry on reading a book, but they do need to be able to get out of there with their dignity intact.  

So a hard and fast definition of borrowed light for emergency lighting purposes is required along with the expected outcome.

Considering the speedy and up to date nature of the civil service, they were probably expecting the street lights to be gas, and the building lights to be electric, and simultaneous  failure of both to be most unlikely.

I'm reminded of the tale of an elderly relative reassuring a friend going the the dentist to have a troublesome back tooth extracted  

“ I'm sure it wont be that bad,  he will be using gas for  that won't he ?”

“ Oh no, they've had electricity for a while now,   you know, put in just after the war I think…”

Given the rise of the LED based fittings, exceeding the bare minimum of battery backed lighting has probably  never been easier or cheaper.

Mike.

mapj1: 
A non electric  example - a height of ‘six-two’  meaning six foot two, not 6.2cm  is processed by an unthinking computer and told his BMI is dangerous . Funny in that case, and luckily obvious, but it shows a worrying lack of error checking in the code and the wider process  that nothing and nobody said ‘that’s silly, no-one is that small…'

The underlying problem is that some people have no grasp of orders of magnitude. There have been tragedies where 10 x (or more) of the correct dose has been administered. Imagine opening 10 or 20 vials and fitting them into a large syringe!

Perhaps like ordering 1000 m of T&E for one small job?

The other problem is just poor software. If you enter a height of 62 cm, but the the age is 6 months, that's just average, but otherwise the software should flag up the possibility of an error. And don't forget that we were all 6.2 cm once - somewhere around a 7½ week embryo. ?

oddly this very morning as I went to my local screw fix to pick up a box of ten hacksaw blades among some other stuff, and was given a large box.   I got to the car and as I loaded up then thought about it, and looked Inside, to see ten smaller boxes, each one of those holding ten blades.

They were rather embarrassed when I went straight back in to return the 90 blades I had not ordered or paid for.  

Computer said part XX, label on the big box said XX too. Application of original thought or common sense, not a lot.

Mike.

mapj1: 
 

oddly this very morning as I went to my local screw fix to pick up a box of ten hacksaw blades among some other stuff, and was given a large box.   I got to the car and as I loaded up then thought about it, and looked Inside, to see ten smaller boxes, each one of those holding ten blades.

They were rather embarrassed when I went straight back in to return the 90 blades I had not ordered or paid for.  

Computer said part XX, label on the big box said XX too. Application of original thought or common sense, not a lot.

Mike.

I must phone my broker, Kingfisher, sell, sell, sell. Kingfisher Group used to own that ubiquitous chain found on every U.K. high street, Woolworths.

Z.

Better than my experience a few years back - motorized valves were supplied by the manufacturer in two identical looking cardboard boxes - one containing the valve body, the other the motor head - sellotaped together at the factory to form one delivery unit. Somewhere along the line someone had presumed that the each box must contain a whole unit and had split the pairs of boxes apart. Orders for one motorized valve thus yielded either a valve body or a solitary motor on a random basis - and replacements after complaints yielded the same. It took some patience with the call centre to get that one sorted out… 

Fortunately such incidents are rare.

   - Andy.