How to assess ground level light using Lux meter

Try not to over think it. go to an adequately lighted alternate location and take reading at night, this will give you a baseline. "Adequately lighted" is an area that is fully illuminated with no dark areas, no place for people to suspect someone might be lurking.

the area lighting should not be harsh, cold light, Mercury vapor lighting works well if you don't mind the orange hue. You might call your local electrical utility and speak with one of their street lighting technicians, they can help you out.

Thank you for your response. i am conducting the survey as part of a litigation case to establish whether or not the platform had adequate lighting at the time of the accident. I am somewhat puzzled as to how to accurately reflect not only the general lighting levels at eye level but also the amount of lighting if the plaintiff was looking down at the platform edge.

"Mercury vapor lighting works well if you don't mind the orange hue. "

Most jurisdictions now prohibit the use of Mercury Vapor street lights with the blue light that interferes with astronomical observations as well as for safety reasons.

Street lighting is generally Sodium Vapor lamps with the yellow-orange light output.

If this has anything to do with a claim that may end up in court you better get professionals to assist you.

yes, thus the suggestion of giving a ring to the local electrical utility.

If it's for a claim, I'd think about contacting your local Health and saftey! They have specialists in this field and it would be in your favour if they also found low light levels!

Start by making a sketch with at least distances and heights. Note any trees, shrubs and other obstructions.

Take photos of the general picture, the labeled light fittings. and the view of the lights from the accident scene,

Take lux readings pointing to the source. (the reflected light will depend on the objects and orientation.) Also take readings of reflected light more or less off the same situation.

A light fitting has a characteristic distribution pattern, if you could post the detail somebody on CR4 may have it for you. You may estimate a pattern by taking a series of readings going closer to the source.

Ther eyes of older people does not adapt to light changes that easy. the patient should be tested.

Get help from anywhere you can. (the sport stadium manager may also be a good contact)

from where are you?

Hello young munsters

You do not advise location of the event, I assume you are in a British Crown Colony: British Isles, USA, Canada, Australia, New Zealand etc.

If you are elsewhere, the legal terminology may be different.

Draw a plan to scale, of the station and environs where the incident occurred.

If the station was crowded at the time, you need to take that into account, take two sets of Lux readings, one with station almost empty, one crowded.

Very Important:

Take a Lighting Engineer, (an Expert) with you as you take the Measurements, get that expert to confirm all readings, and date and sign the charts and plans you are going to make, after those charts are completed.

Ensure your expert signs a Statutory Declaration or US equivalent, stating that he was there when those readings were taken, on the date, and that they are all true and correct according to the attached (stamped/witnessed by JP or Notary Public) Charts and Tables.

Holding the Lux Meter at waist height, (1 metre above ground/floor level), walk around in the direction the pedestrian walked, take plenty of readings in a small grid pattern, every foot or metre, depending on how detailed you need the readings.

If needed, use a closer grid pattern near the accident/incident location. (Fine details)

Plot those readings onto your scale plan.

Now you should have dozens or hundreds of spot points, in a regular pattern, and each point has a Lux level associated.

Now you can join up the points of similar light level, in the same way as Isobar lines are drawn onto Weather maps.

Retain a full copy of the absolute (Lux Meter Level spot readings) in the form of a Table, with co-ordinates in one direction as Alphabetical, and in the other direction (at right angles to the first direction) Numerical - Use MS Office Excel Table or equivalent for this.

So....First spot would be A1, next spot A2......A3, A4 and so on

Next row B1, B2, B3.....etc.

So now you have this fine chart, with the light levels drawn across it, plus the chart recording the absolute measured spot points.

Also make notes of the surfaces: Slipperiness, whether accident/incident happened on a wet day, or floor recently mopped or washed, colour of surface/s - (dark colours/black absorb light, light colours reflect), and whatever else may have a bearing on the accident/incident.

Now you have Evidence - but remember that lamps may have been replaced since the accident/incident, and you may not be able to obtain proof of that.

If you intend litigation, remember that Utility companies, such as public transport organisations (railway stations and the like) have insurance, but those Insurers are not really interested in paying out, they are in business to take the premiums in, to make money for the Shareholders, not pay out to claimants.

Thus you may well have an expensive fight on your hands.

This means you need expert opinion, careful detailed records, Charts, Light level Tables and the like, to press your case through to a satisfactory and fair conclusion.

Advise your progress here

Kind Regards....

To add to sparky's answer, there are some additional and absolutely essential points:

1. The light meter must be appropriate (i.e. by a recognised manufacturer and to a recognised standard). You need to get advice on the legal meaning of the word appropriate in your country. The sensor must be suitable for the type of lamps (fluorescent, sodium, mercury discharge, etc).

2. The meter must be recently calibrated by an attributed body.

3. You cannot walk around with the sensor at waist height. You must have a calibrated stand (see http://www.cibse.org/docs/factf3.doc). However, external lighting levels are defined at floor level, not at a height.

4. If part of your court argument involves inferring that certain luminaires were not working at the time (you can sequester CCTV tapes if available, or eye witness affidavits), you must carry out the readings with these fittings both on and off. That means removing the lamps (you can't cover the fitting that is known as falsifying the environment). Now you're in stickyville, because you cannot knowingly put the public in danger. So you have to make extensive arrangements in advance.

5. Be acutely aware of changes to the environment. Depends on timescale but includes: trimming vegetation, painting, posters (changes reflectances), lit shop windows etc.

There's much much more. You really need an expert (again legally defined) with suitable legal experience. As said, the insurers will fight back by any and all means. You need to cover all the bases in the first instance otherwise the case will be adjourned and could drag on for a long time.

I'm not a registered user here but will be in about 48 hrs. So I won't be able to see replies. I have to click the email thing. Anyway... I use to do surveys (anything related to OSHA) in the USAF. I did many lighting surveys for industrial and non-industrial areas. You might want to get a hold of the current IES lighting handbook or any other published criteria. This will give you a reference in court. The IES book does have "recommended criteria". For legal issues, consult a Certified Industrial Hygienist CIH) they will have the respect and weight of any info. provided in litigation. I'm sure I read somewhere around 1995 that a CIH in court is paid about $125/hr. If you want to go cheaper a certified Occupational Health and Safety Tech. would also have some insight.

Hello "Guest",

Thanks for your helpful reply, and looking forward to seeing more of you, with your Member Name, at CR4 Forum.

Kind Regards....

Thank you all for your responses, I got some shock this morning when i logged on and saw all the replies. I believe from reading your comments that i would be best advised to contract a registered professional as i am clearly out of my depth. I am residing in Ireland by the way. Thank you all for your comments once again and I will update this thread with any developments.

Hello young munsters

'tis the top of the mornin' to yourself, from what was once called "New Munster" = New Zealand's South Island

If the person who had the accident/incident had drunk too much Guinnessthe chances of a successful claim are minimised.

The Professional is very important, because if it comes to a Court situation, a Professional is considered as "Expert Opinion", and thus is hard to refute.

Kind Regards....

Hello All... a couple of other points to consider:

From a street lighting point of view (from Los Angeles):

1. Determine what authority governs your location and there will be an appropriate recommended lighting level. If Ireland, perhaps it is the CIE which provides lighting standards for most of Europe. (Also, has the local authority adopted these standards for their safety lighting design?)

2. Determine classification of area of incident as most publications have various recommended lighting levels such as railway or mixed (vehicle/ped) pedways. You may have to count the number of pedestrians (peak & off-peak) to determine level of usage.

3. Often, security lighting for pedestrian walkways can be specified by the level of vertical illuminance (just 90 degrees off) - this allows the ped to identify surroundings and makeout details (to determine friend or foe). The quality (glare/shield) and color (lamp source type) also play important roles in this factor, but somewhat subjective.

Yes, find a local expert for professional opinion and legal interpretation...

I found comments by Sparkstation helpful and reference document by BabyGuinness excellent. thanks!

good luck ! (Mmmmm Guinness)