Gymnasium Lighting 4

[lenback]

I work with a design/build commercial general contractor and we are constructing a family life building for a local church. This building is approximately 16,000 sf and includes a full size basketball court. The size of the gymnasium is 70' x 100'. On previous similar projects, our electrical engineer used 20 high bay fixtures with 400 watt metal halide "super" bulbs mounted at a height of approximately 24'. On this particular project, the church wanted to be able to connect the lights to their theatrical lighting dimmer panel (the building includes a stage for plays). In this case the electrical engineer used 24 "cylinder type" fixtures with 500 watt quartz fixtures installed at a height of 24'. The power has just been connected and the lights turned on. The gym floor appears dim and the church has already started complaining. We called the electrical engineer to come look at the situation and give us his opinion. He informed us that he normally designs lighting for this type building to be around 25 - 30 footcandles. When he checked it with his light meter, it read exactly 30 footcandles. His opinion was that we had exactly what he designed and there should be no problem. He admitted that he would have designed for 50 footcandles if the gym was going to be used for high school tournaments and around 100 footcandles if games were going to be televised. That did not satisfy the building committee and, now, they are wanting additional lighting at no additional charge. My question is, What is a reasonable footcandle design for this situation? I must admit that the lighting does look dim and I would not be too happy if the building were mine.

 

[peebee]

A quick GoodSearch using the following....

http://www.goodsearch.com/Search.aspx?Keywords=ies+gymnasium+footcandles

...turned up a North Carolina High School Athletic Association (NCHSAA) document indicating a target 50fc for gymnasiums for practice or recreational purposes only, target 80fc where there would be spectators.

You should get your hands on the IES recommended practice for sports lighting document (

http://www.amazon.com/dp/0879950285...=380333&creativeASIN=0879950285&linkCode=asn)

if you really want a definitive answer.

 

[peebee]

PS -- you might get a better response to your question if you post it in the "L:ighting and wiring equipment engineering" forum.

 

[DaveScott]

See the link below for an idea for lighting levels. 1 foot-candle is 10.76 Lux, so your gymnasium is 322 Lux. Looking at the link, 322 Lux does look a little on the lower side, but I have another thought: if your lights are similar to 'downlighters', then the room will appear to be darker because the verical surfaces will be relatively unlit, and those vertical surfaces are the ones that you see more, when looking around the room.

 

[DaveScott]

Sorry; forgot the link.

http://www.megavolt.co.il/Tips_and_info/lightlevel.html

 

[itsmoked]

Doesn't look low to me.

It's too bad. The Lighting Engineer or the architect should've been sharp enough to recognize this as a possible tripping point and invited the customer to a few locations and asked them, "Is this bright enough?". Think of the disappointment and hassle it would've avoided. Even a light meter in the sanctuary would've been very educational.

Otherwise the customer signed off on the plans. The price they paid was for the amount of light they received. They want more light, they need to pay more for it. You could do the change engineering gratis but otherwise they should pay.

Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com

 

[waross]

Hi Keith;
I am usually in agreement with you but not completely this time.

Otherwise the customer signed off on the plans.

How many times in these fora have OPs been advised to "Consult a professional."
The customer consulted a professional and for whatever reason(s) got a bad installation. I haven't done lighting calculations for decades, but as I remember there is more to it than just measuring light intensity with a meter. There are contrast ratios to consider and different recommended mounting heights and horizontal spacings for different types of fixtures. It is possible that the precepted problem is related to contrast ratios or spacing rather than foot candle levels.
The jurisdiction that I worked in had lighting levels and contrast levels set by the factories act. I saw a few installations that did not pass inspection. In one instance the supplier who had done the calculations supplied the extra fixtures to come up to standard. I don't remember who ate the labour.
In another instance the contractor raised the red flag at an early stage and the customer had the lighting redone by a second engineer. The customer was a little nervous by now and asked the contractor to have the new design vetted. It then fell to me to get up to speed on lighting and the factories act and check the design. The new design checked out OK and the installation passed inspection with no problem.
Back to the OP. Is a P.Eng. stamp a mark of excellence and competence or a shield to hide behind?
I hesitate to state a percentage of the change cost that the engineer may be responsible for, but I suggest that it may be a little more than just free re-engineering.
The happiest solution is a mutual agreement on the cost splitting.
The engineer can write his extra costs off against his continuing education budget, and his public relations budget.
respectfully

 

[itsmoked]

Hi Bill,

The point I'm trying to make is that the customer paid for only so much light. It may be too little but that's all they paid for.

They were provided the minimum suggested amount of light not less than the minimum. Less than the minimum would be wholly the designer's/contractor's problem.

If you go to the store and buy a 60W bulb come home and screw it into your socket and decide afterwords it's not bright enough, is it the store's fault? Should the store foot part of the bill to provide a 75W bulb? I don't think so.

<in my opinion anyway>

Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com

 

[waross]

The point that I am trying to make is the difference between my guessing that I need 60 watts when I need 75 watts and the other situation where I realise that I don't know how much light I need so I pay a professional to tell me, and the professional gives me the wrong information.
This is just secondary points of view because we don't know for sure if the lighting level is adequate, but it may be doubtful.
The other complication is that the initial installation may have cost $10,000 when a proper installation would have cost $15,000. The total cost after changes may reach $20,000.
Did the customer ask for 50 fc or did he ask for adequate lighting?
In my first experience the lighting was already installed when the deficiency became known. The supplier took responsibility for the mistake and supplied the extra (explosion proof) fixtures at no cost.
In my second experience the mistake was discovered before any fixtures were bought and before any work was done and the customer paid the whole cost of the installation. In addition to the lighting problems the utility would not accept the main service layout. The customer had a second engineer redo the design.
Sometimes to correct a bad design after installation, not only are additional fixtures needed but the spacing must be changed also. That gets expensive. Whose fault and who pays for the added expense?
Respectfully

 

[EEJaime]

I have designed gymnasiums for a multitude of sports, at many levels of competition. The Illumination Engineering Society has for a basketball gym, Class I through Class IV requirements, which are from professional, (the NBA has even higher requirements), to community center type activities. Many organizations, such as the NCAA or other sporting organizations even at the high school level have requirements approaching those of televised sports, which would be a Class I facility. The lighting is recommended at 125 footcandles, (1250 Lux), down to 30 footcandles, (300 Lux), for the least restrictive application.

As a lighting designer it is incumbant on us to make an effort to provide the owner with a clear idea of what he is buying. That is not always an easy task and no matter how much we try, sometimes it still turns out "not exactly as I pictured it" to an owner.

In this case it appears to me that the designer was at the absolute bottom of the scale starting out. Normally we would have sufficient lighting to at least allow the installation to "burn in" - which means initial footcandle levels 10-15% higher than maintained levels. The lighting output will drop as the lamps age and the fixtures get dirty. Quartz is not a very good source for this application, (it would not be allowed in California as the efficacy does not meet state energy standards).

This installation should have been comprised of a basketball lighting system with a seperate assembly for the stage performances which would be controlled by the dimming system. Being a church facility, I imagine budget was an overriding concern, but these really are two distinct types of lighting systems which are difficult if not impossible to combine.

Again, not all electrical engineers, and not even commercial electical consultants are lighting designers and even though the installation may "meet code", it can still be a poor installation.

Unfortunately these "design-build" projects are often bid and budgeted before a design professional does a detailed design and the facility may end up with budget as the limiting factor. I have many junior designers jumping at "design efficiency", without taking into account the ultimate consequences. Lighting design is not a hard numbers arena, there are many ways to skin this particular cat and many considerations as to the tools used to do so. It appears not all options were considered here.