Things to make an ice skating facility cheaper to operate

[Query]

In line with the thread on improving rink acoustics, it makes sense to think about other rink design factors. We've had various threads on how to make them better for skaters, but not so much on how to make them cheaper to operate - which is a major factor determining the economic viability of a rink, and how often the rink is willing to run sessions.

For example, if you spend a few thousand to a few tens of thousands of dollars extra at the outset, and you know what to do, you can make electric and plumbing much more reliable. According to an electrician of my acquaintance, it's the difference between major electrical repairs every few years, and every 50-100 years. (He is guessing somewhat - electric wiring using current methods hasn't been around that long.) Proper motor/pump choice and installation also cuts down substantially on electric costs. And plumbing repairs changes from every few years, to every 30 or 40 years. Also, 1-2 orders of magnitude fewer toilet clogs (that's all a matter of the pressure reaching the toilets, and the resistance provided by the drains). Another thing you can do is make it possible to service the wiring and plumbing without knocking down the walls, and there are design things you can do to cut down vandalism. The savings on maintenance and repairs pays itself back in a year or two, saving thousands or tens of thousands of dollars a year.

Problem is, very few building engineers, electricians or plumbers know how to do it, and doing it right makes their initial bid a little higher.

A USDA building engineer told me you can also use materials that don't need repainting. That adds significantly to cost, but it's worth it in the long run.

A rink manager who's been at several rinks told me that building and workstation layout has a tremendous affect on off-peak time operating costs. If one person can see everything, and doesn't have to move much to handle everything, then one people can handle everything (admissions, rentals, snacks, ice monitoring, music). [Two people if you want to surface the ice while taking admissions money, and two provides an extra margin of safety.] At other facilities, you need 10 or more people. You can also choose cool lighting (like LED lighting) that doesn't significantly increase dehumidifier and cooling load to turn on. That's the difference between it being economically worthwhile to have freestyle sessions, or stick and puck sessions, with an average attendance of 1, to needing a lot more. It saves costs during peak hours too, though you need more people then.

There are a variety of things you can do to cut dehumidification, heating and cooling costs. Of course, you have to spend extra for an electric ice surfacer so you can seal the building better without carbon monoxide being an issue.

There should be an economically practical way to cover the ice when not in use, to cut dehumidifier and cooling costs.

[Skittl1321]

Our rink doesn't always turn the lights on if enough light is coming through the windows.

We also usually only have one staff person during off peak time.  You just can't pay during a zamboni break, and after they take your admission money, they walk over to skate check to get you a pair of skates.  During LTS there is an insane crowd of people asking questions at the desk, but usually only 2 people working.  Rather than having someone at skate check, they set out a huge array of skates on the counter- so a LTS student can just go pick up a pair of skates on their own, no skate check employee needed.

I have no idea what they do in terms of facility equipment, but a few years ago they took the padding off the sides of the benches in the lobby and painted it black instead.  You have to be careful not to hit your skate blade on it, but they no longer have to replace it all the time.  They also finally padded the concrete ramps that used to say "no skates"- i'm guessing it saved a lot of damage to the rental skates.

[VAsk8r]

Our rink doesn't always turn the lights on if enough light is coming through the windows.

We also usually only have one staff person during off peak time.  You just can't pay during a zamboni break, and after they take your admission money, they walk over to skate check to get you a pair of skates.  During LTS there is an insane crowd of people asking questions at the desk, but usually only 2 people working.  Rather than having someone at skate check, they set out a huge array of skates on the counter- so a LTS student can just go pick up a pair of skates on their own, no skate check employee needed.

My rink does these things too, except you can't select your rental skates. Only employees are allowed in the room with the rental skates. There's really not anyplace to lay out rental skates without crowding and chaos during a crowded public, although I could see this working well on the sparsely attended ones.

I think the approach of having fewer employees sometimes backfires. If people have to wait to pay because all the employees are doing something else, it comes across as poor customer service.

Another thing my rink did recently was to install solar panels on the roof using a low-interest (maybe no interest?) loan they got through some program. Utility costs are a MAJOR issue at my rink in particular because it has huge windows overlooking the ice.

Some people complain when they don't turn the lights on, but I don't mind. I'd rather have them save the money as long as I can still see.

[Query]

A lot of the rinks I've used have very time-inefficient ways of paying for sessions, or to sign up for classes, involving a computer that connects to an off-site computer, or requires a lot of keystrokes and mouse motions. That sometimes wastes many minutes / person.

---

I feel that all rinks should have mats showing the size and shape of every size and model of rental skate offered, with brief instructions on fitting boots, so most people can figure out their own size.

I also feel there should be instructions telling people how to lace boots next to the mat. Not only do poorly laced boots delay the entry of everyone onto the ice, but they sometimes break down a pair of rental boots in one or two sessions - very costly.

---

I think it isn't always true that you save energy by using windows to provide light. Even when you do, it may be appropriate to place venetian blinds over the windows when you don't need their light.

---

A manager tells me that it is usually possible to figure out when many people will show up for an off-peak hour session. They request that group leaders inform the rink in advance. They also keep track of when a local school system plans to have a day off. However, there is nothing wrong with having a call list to call for extra help, though they will come a bit late.

---

If a lot of people come to the desk to ask questions, something is wrong. Large print, well organized  signs should provide all that most people need to know.

---

I'll try to summarize in a day or two the things I've been told help with long term electric and plumbing reliability. A lot of it is just providing a little extra capacity, and having people properly trained to do installations and maintenance. This is partly a matter of meeting building codes, but a lot of it is in the category of "best practices". There is also the matter of making it easy for maintenance personnel to access electric and plumbing lines and fixtures, without making it too easy for people who love to commit vandalism.

[jjane45]

Nice ideas, I found the skate size mat especially interesting

[angelgirls29]

The mat sizer thing wouldn't be too hard to trial.
Get a yoga mat, pull the insoles out of the skates, draw round them and colour it in with a sharpie or similar. Then they could see if it works before they do it on a bigger scale.

Alternatively they could have a few of those shoe-sizer things you get in shoe shops.

We usually (non-peak) have one staff-member doing the front counter and skate hire. I've waited for 10/15 minutes to pay as they were at skate hire. It would've been really easy to just walk in, put my skates on and skate (but I'm too honest and would feel really bad!).
If the wait was more like 5 minutes, it would be better.

Also, when you have a larger (school or similar) group, you could get them to write their shoe size on the permission slip (our rink doesn't do this) so they could make sure they've got the right amount at the right size all ready to go.

[Query]

Best Practices
(Long and technical!)
(Sorry if this is a bit disorganized!)

Most of this is based on information from an electrician. He worked for a university with over 30,000 students and 200 buildings, at several sites, for about 25 years. He had a general master electrician license, was certified to work on high voltage switching (but not splicing) and on alarm installation, and was a licensed fire inspector. He was trained to install appliances, but not to service them. He was not trained to do air conditioning and refrigeration work (such as is needed to work on ice rinks), he only did minor plumbing. Because he specialized to some extant in motors and pumps, he frequently worked in conjunction with a master plumber, with motor and pump repair shops. Almost everyone working in the trades does minor carpentry (e.g., drywall), but he was not a carpenter per se.

He handled about half of the electrical work calls for his shop at the university, including most of the difficult problems. In short, he and one other electrician of similar skill could have replaced the other 29 electricians and the shop foreman who supervised the whole bunch.

None of the other electricians earned master's licenses - and partly because he bought fancy tools - e.g., both mean and RMS responding amp meters, tick tracers, first class hand and power tools. He is also a curious person who did things most electricians do not - e.g., tried to figure out which methods led to fewer repairs, talked to building engineers and members of other shops, telephoned companies that make electrical components like motors and transformers, and he spoke to the engineers who designed those components.

The master plumber had a similar relationship with his shop, which also had about 30 people - who could have been replaced by a second good one.

The university maintenance department clearly had management issues. The university provided no benefits or pay raises to electricians or plumbers who went beyond their most basic apprentice licenses, and did not pay significant attention to time-to-complete-work, or to return-call-rate. Good people usually cost more, but if they make the effort to become good at their jobs, they can save a lot of time and money in the end. Almost all his calls were to repair stuff the other electricians had messed up, or which contractors who had been hired to do work such as building new buildings had done imperfectly. The university was part of a government, which was exempt from the rules requiring electric and plumbing inspection, which may have affected the level of work done by staff and contractors. They apparently did not pay much attention to the maintenance requirements on work previously done by the contractors they hired.

Likewise, the university, when reviewing proposals for buildings, did not consult the maintenance department. (Two modern building engineers tell me this is less common now - engineers and architects frequently consult maintenance people, though not always the best.)

Many of the buildings are quite beautiful, and won architectural awards. But they have substantial maintenance requirements. For example, a hot tub was placed in a basement, below the level of the main drain. A single sewage ejector pump was used to pump the drain water from the basement up to the main drain. But there were no pumps made that were rated to take the outflow temperature of the hot tub. So every few weeks, the sewage ejector pump would fail, backing up drain water (including toilet water) into the hot tub. This created a health and safety issue, as well as a maintenance issue. In the end the electrician, plumber, motor shop and a pump shop got together and rebuilt two motors, on separate electrical circuits, so they could take the outflow temperature - but this is not an ideal solution either, because all devices must eventually fail. Any normal electrician following standard operating procedure would replace the motor with the closest equivalent, and would not know about or be able to make all the modifications. Fortunately the hot tub is no longer in operation.

It is very important that pumps operate within their rated temperature ranges.

So - if you must install a plumbing device like a hot tub with a high outflow temperature, make sure it is above the level of the main drain.

Again, the electrical department looked at a gorgeous  new recreation building, lighted by a big light bulb in a tower that stood high above the swimming pool, and thought that the only way they could replace the expensive light bulb would be to drain the pool, then tear down and rebuild the tower.

Conclusion: it is better design to make it easy to access electrical appliances, such as lighting and sound systems. If they must be high up, provide stairs and reasonably safe cat walks. Make it possible to service the appliances without shutting the facility down or rebuilding buildings.

It may not be practical for a single ice rink facility to hire the most expert installation and maintenance people full time. But some of the same potential management issues apply.

----

Whenever possible, local on-site personnel that are left to manage the rink at all times should be trained to do minor maintenance. For example, most calls to electricians turn out to be plugs that have come out of their electric outlets, or breakers that have thrown themselves. Personnel should also be able to change light bulbs, when possible. Make a note of the problem, and if it recurs often, call the electrician, but not otherwise.

Train on-site personnel to access the breaker panel, and the plumbing shut off valves. Make it easy to figure out which breakers control which devices, and provide a shut-off valve for each plumbing appliance.

Elevator doors can be opened in a minute or two from the outside by accessing a button hidden above the door. Fire departments are not trained to do this - they use heavy duty hydraulic equipment to force the door open, causing thousands or tens of thousands of dollars of damage. Train your staff to do it right, before the fire department is called. This will save money. In addition, people stuck in elevators often get very upset.

Make sure the on-site personnel know how to dry floors if they get wet.

Make sure the on-site personnel have the numbers of emergency staff to call if needed, including facility managers, electricians and plumbers.

These things seem trivial, but can be a very big deal.

----

Speaking of elevators, do not rely on handsets in the elevator for emergency calls. It was the electrician's experience that most handsets have been disabled by vandalism. You want something like a red emergency call button, that is less easily damaged.

In general, all emergency devices, as well as handicap access buttons, need to be tested on a frequent basis.

Bees, wasps, and birds love attics that have open windows at each end. Screens make a huge difference.

Bees and wasps are a health and safety problem. They repell customers, and create potential liability.

Bees and especially wasps don't fly very far. If you see a new nest, there is another nearby.

If there are any holes in siding, bees and wasps will nest inside. Likewise for stone work.

Windows need to be of a standard size that is easily replaced by off-the-shelf products. Actually, that is a good idea for many things, like bathroom fixtures.

Window air conditioners are very trouble prone. (Note however, that the similar heat pumps used in hotel rooms are more reliable.) In addition, birds are constantly nesting on the ledge created by the open window, or underneath the AC unit. They are happy to peck into the wood around the AC to make this possible, and they do a variety of things that can make the wood rot. It may be possible to create windows that are of just the right size that that is impossible to do so. Or it may be possible to place screens or chicken wire around the unit so there is no ledge.

Chimneys need to be covered with screens to keep birds out. They reek all kinds of havoc in the furnace. Then they die, attract flies, and stink.

I'm not sure if there is anything that can keep sparrows out of drain pipes. Sparrows love to nest inside, and plug up the pipes.

There are a variety of products to insure that the drains at the top of building eves don't clog with leaves.

----

Iron pipes WILL rust, and develop holes. Don't use iron!

Underground drain pipes often leak a little. This attracts roots from trees and bushes, which then grow into the pipes and destroy or clog them. Some trees and bushes are much, much more prone to do this than others - find out which, and avoid them like the plague.

Trees with branches over or near buildings are a maintenance and safety problem just waiting to happen.

Overhead line insulation weathers off. Most overhead line electrical problems are caused by squirrels. Your lines should be held apart far enough that squirrels can't bridge the gap. Wider is better - some birds have long wing spans.

Do not place side walks to make the overhead design pretty, or where you think people will walk. Start with grass, look where they walk, then install the side-walks. If you don't, people will ignore your pretty side walks, and walk on the grass.

----

All electrical connections should be made as though they are outdoor or underwater connections, because there is always a risk they will get wet. Use a conductive grease. Alcon De-Ox is best - Ideal No-Ox (a conductive oil) is much more common,  but is messier, so it may short out the circuit if you mess up, and it is not properly designed for copper-to-copper connections. Cover the connection in shrink wrap tubing, and use a heat gun to shrink it. Wrapping electrical tape around the connection does not work as well. The extra work of waterproofing the connection takes less than a minute with practice, but makes a huge difference in long term reliability.

The NEC frequently requires that wires are run in pipes. But it does not require that it be possible for the pipes to drain if water gets inside. The geometry of the pipes, including bends around obstructing objects, should be designed so that drainage will occur! A very frequent error. Water destroys the electrical insulation, causing shorts and possibly fires.

----

After you tighten down a connection between a terminal and wire(s), come back 24 hours and retighten. I don't know why this helps, but he says it makes a big difference.

To make sure screwed down connections don't work their way loose (making a poor connection), you must apply pressure. This can be done either of two ways:

(1) Double nut. I.E., screw a second nut over top the first one, and tighten them hard against one another.

(2) Use a lock washer. Incidentally, some washer head screws have integral lock washers.

By the way, the same principle applies to all bolt and nut connections.

I sometimes like to grease bolts and nuts so they don't rust, on things like car racks. But an auto mechanic told me this is considered a bad idea in vehicle work, because grease makes bolts and nuts go loose. So I don't know what the best practice is for preventing steel nuts from rusting.

Good quality stainless steel screws, bolts and nuts rust less and last longer. Pure titanium (not titanium steel) is much better, where you can afford it.

----

MOTORS

Throughout the following discussions, I assume you are in the U.S., and that U.S. conventions on voltage and frequency apply.

When motors stay in start mode, the windings tend to burn out, and they consume more power.

1. The most likely cause is supply voltage: Is the pump motor getting the voltage it is rated for (on the base plate)? Most motors are rated for 230 VAC, but some transformers only deliver 208 VAC. Voltage drop in wires reduces it further. Measure the voltage at the motor while running. There are several solutions to low voltage:

 A. Increase the wire gauge feeding the motor. The United states National Electrical Code [NEC] requires wires be large enough gauge so they don't burn up, but does not regulate voltage drop, so meeting NEC is not good enough. Larger gauge wires are always better.

 B. Boost the voltage: adding buck boost transformers, or change the tap setting on the building transformer. In either case, shut down building electricity first. Changing voltage may damage other things on affected circuits; consult with the building engineer!

 C. Go to a good motor repair shop, and have them rewind the motor windings for the measured voltage. Most motor repair shop just shorten the windings, resulting in inadequate current, poor performance, and overheating. A good rule of thumb: pick the new wire guage so that the mass of metal in the windings does not decrease.

2. If the motor is not coming up to the rated shaft speed (at which the amperage will be about 80% of the rated code amperage on the base plate), there are several possible reasons.

 A. Too much water may be flowing through the pump. Close the outflow valve. The motor will increase in speed (no flow=small motor load=low amperage). Slowly increase the valve opening until you get 80%-of-base-plate amperage. This may fix the problem, and also reduces impeller cavitation.

 B. If the motor or pump do not have sealed bearings, they may have been greased incorrectly, which means they overheat and rust.

   (1) You have to remove the cap to add grease. (Don't laugh. Electricians only read the NEC, and are not mechanics.)

   (2) Do not replace the cap until you have run the motor for at least a minute, or until the grease stops coming out. Too much grease does as much damage as none. Then replace the cap.

 C. The bearings on the pump or motor may be going bad. If you put a large screw driver blade over top the bearing, and listen to the handle, you will be able to hear it. A motor repair shop can replace bearings.

 D. Check if there are shims beneath the motor. If not, it must be aligned by a competent motor installer. Even with shims, you may have a borderline badly done motor installation, which triggers the problem given a borderline situation. Here is part of what a good motor installer checks to see if everything is right:

   (1) If the motor-to-pump coupling vibrates, they are badly aligned. Flexible couplings do not eliminate the need for proper alignment. Bearings wear out from off-axis motion.

   (2) There must be some play in the coupling along the direction of the shaft, because the shaft of a motor needs to center itself on the magnetic field of the motor, and bearings can't rotate if the distance is too close. If you mark the motor shaft position with a pencil when the coupling isn't connected, the position should not alter when you connect it.

EDIT: Correctly installed and powered and maintained motors should last virtually forever. (He says sealed bearings need to be replaced every 10 years, greased bearings every 15, but he believes the rest of the motor should not fail, virtually forever - unless something heats up the wires - which only happens if something is installed wrong or the wrong voltage is applied. If the overload is a fuse, it may need to be replaced when the bearings go bad.) Badly installed motors may last for a few weeks or months.

3. The motor may be under-rated for the job. To some extant, larger motors are always a good idea. Small motors overheat (reducing motor lifetime), and sometimes have trouble doing what is needed. In addition, they actually use more current than a larger motor, when struggling to keep up, especially if they stay in start mode.

4. Many pumps need to be primed by pouring water into the outflow port.

5. For pools and hot tubs, if some jets don't work, try blocking the jets that work. The extra pressure may make the other jets work, or force air out of the line.

6. The water from things like pools probably drains directly into the pump. But if the pump instead works out of an open pool, there may be too much head pressure for the pump. Drill a hole in the pipe a couple feet over the pump, and insert and seal a smaller pipe with a valve. Let water bleed out the small pipe until the motor comes up to speed.

7. Motors must be protected by "overload" fuses or breakers, so they won't overheat or burn out if stuck in start mode. Almost any of the above problems should have tripped or burned out a properly rated overload. For U.S. motor manufacturers, the base plate (code) current is the rating of the desired overload, NOT the running current. Unfortunately the electric code doesn't say this, so most electricians boost that value by 25% to get a higher overload rating, because that is what they are supposed to do for almost all types of appliances. That error means the overload does not protect the motor, and the motor may have a shorter lifetime. If your electrician doesn't believe this, have him call the motor company and speak to the engineers. It is a good idea to get overloads right, because motors cost much more than overloads.

8. If you have two pumps (one active, one stand-by), and the valve is open on the stand-by, you get back circulation through the stand-by. Make sure the valve is closed on the stand-by pump. If the alternator or contactor is not working right, you may be getting current in both pumps, which also creates problems, so check that the stand-bye shaft is not rotating.

9. The motor may have borderline overheating problems. For hot tubs, try using cold water in the bath until the problem goes away.

10. Call the hot tub manufacturer for suggestions. They may be able to send out a service representative or certified pump installation specialist. If not a Jacuzzi shop may be able to help.

11. Don't exceed the head pressure for a pump by pumping beyond it's rated height. Pumps should never be placed in series. At start-up, each pump receives pressure from the whole column. Pump into an intermediate pool, than run another pump from the pool. For sewage ejector pumps, the intermediate pool can not be exposed to the atmosphere, because it stinks.

-----

SUB-PUMPS and SEWAGE EJECTOR PUMPS

Most of the above applies.

As a general rule sewage ejector pumps are more ruggedly made than ordinary water pumps used as sub-pumps. Use them if you can afford to. If not, replace the impeller blade with the sewage pump equivalent.

Sub-pumps should always be installed in pairs, so if one fails, the other continues. The two pumps should be on seperate circuits. Battery back-up, or generator back-up, is a good idea.

The sensors for the two pumps should be electrically switched with each other, so they both run some of the time.  Mechanical switching devices are much more reliable than electronic ones.

The amount of water a sub-pump needs to pump is enormously affected by surface water hydrology. In particular, if you landscape the ground so that it is high next to the building, it helps a lot. Absolutely make sure that drainage ditches can not overflow into basements! Also streams - remember that streams flood, and beavers make dams.

Drain water stinks. Sewage ejector pumps should be in sealed

Never place the control circuitry below the level to which the water could flood if the pumps fail. This is an almost universal problem in commercially installed outdoor fountains.

Electricians and plumbers should always carry their own portable pumps.

---

REFRIGERANT PUMPS AND COMPRESSORS

This is beyond my expert's knowledge. But most of the same principles should apply.

----

EMERGENCY GENERATORS

Most emergency generators are light duty, and can not run for more than a few hours, for several reasons:

(1) They will fail.

(2) They will run out of fuel. To handle many outages, you need a week or two. Don't count on being able to buy fuel locally, if power fails.

Stay away from "light duty" things in general.

Gasoline and diesel fuels will gunk up if left in the tank more than a month or two. You need to use additives, and run the motors periodically, to clean out the old fuel.

Natural gas generators have far fewer problems. For some reason, at least in my area, natural gas doesn't seem to fail at the same time as electricity.

All generators need to run once in a while so they don't fail. Less of a problem for natural gas.

It is not clear the cost of an emergency generator that can run the compressors of an ice rink is worth it. The rink I know that has one paid $200,000 for it. I guess it depends how often power failures occur, and how much income the rink looses. When an ice rink looses ice, it takes 1-2 weeks to recreate and repaint a good ice surface.

----

Don't assume trades people will slavishly do everything an architect or design engineer will say. Good tradesmen, faced with an uncommon procedure for doing something, will usually substitute tried and true method. There is a well known example where an engineer specified that structural building elements be connected in a special, stronger way. They building collapsed.

This is a good example of why it is a good idea to stay with well-tested, well-established building techniques!

Another reason is that people already know what problems can arise with the old methods, and have worked out ways to deal with the worst. Unexpected problems can arise with new techniques.

Stay with "conservative" design. Over-build, leaving leeway for error. Some architects love to do new and radically different things, things which would have been impossible for yesterday's technology, but which they THINK are just barely possible with today's latest and greatest development. The results may not be what you want.

----

HARMONICS AND TRANSIENTS

Most of the principles encompassed in the NEC and in many of the rules-of-thumb included in electrical engineering textbooks are based on the idea that electrical loads are linear, i.e., that they follow Ohm's Law - that instantaneous current draw will be proportional to instantaneous voltage. It worked pretty well for incandescent light bulbs and electric irons! So if you supply a 60 Hz sin-wave voltage, current will be also be a 60 Hz sin wave, and will be in phase with the voltage.

This has many beautiful consequences.

For example, in an electrical system with two phases, where you might have two 125 VAC hot wires, 1/120 second apart in time,  relative to the common 0V wire (if you look at it that way), the return wire currents from the 125 VAC and 250 VAC phases tend to cancel out, and the return wire never has to carry more than the maximum amperage of the two phases. (I think I got that right. I'm not an electrician.) Likewise, with three phase wiring, the three hot wires differ by 1/180 second from each other, so the return wire never has to carry more than any one phase. If you balance it right, the return current will be near 0. In fact the NEC allows the common (return) wire in three phase wiring to be only rated at 80% of the current capacity of the hot wires, and breakers and fuses are always on the hot wires.

This is also done for the common wire in a two or three phase transformer. The current carrying capacity of the magnetic core of the transformer (which reinforces the magnetic field, linking the two circuits in a linear manner) is also based on pure 60 HZ amperage sin-waves.

The inductance between wires and nearby metal objects is also fairly low, because 60 HZ isn't very high. So nearby metal objects don't get very hot. (Inductive heating is proportional to the square of the frequency. So a 1% level 600 Hz component contributes about as much heat as a 99% 60 Hz component. But Ohm's law says we don't have to worry about that.)

Simple mean-responding breakers and current meters is good enough for pure 60 Hz sin waves of current, even though RMS current is proportional to the heat load on wires. (BTW, mean-responding meters include a calibration that makes them read as though they were measuring RMS voltage and current - as long as the input is a sin-wave.) RMS responding breakers and meters are more expensive and less common.

Unfortunately Ohm's law is a poor model of many modern electrical loads.

For example, for circuits dominated by switching power supplies, such as are used in computers and UPS devices, higher frequency harmonic current loads play a large part. In three phase systems, the return wire current will be about twice that of the hot wires. In addition, mean-responding breakers and mean-responding meters will substantially under-estimate currents.

Flourescent light fixtures can generate substantial harmonics, unless you use good quality ballasts that filter them out. For example, almost all the university buildings had substantial electrical problems and a few had fires after energy saving but cheap ballasts were installed.

Other non-incandescent lighting fixtures can also create non-linear loads - e.g., arc lighting, mercury vapor lighting, LED lighting - if the harmonics aren't filtered well enough. And just incidentally, if your filtering circuit is resonant with the filtering circuit on the outdoor electric lighting pole near you, they may burn each other out.

Wires and pipes may get hot, start fires, causing electrical connections to become poor, or cause other problems.

They may also buzz and shake, cuasing electrical connections to be poor.

Big motors and other big "reactive" loads can create a phase difference between voltage and current. You should use a capacitor bank to compensate. Since running and starting currents are very different, it may be ideal to use an active switched capacitor bank that compensates correctly at different current levels. Reactive loads do not create high frequency harmonics and transients, but motors that receive non-60-Hz-sin-wave current may overheat and burn out.

----

TRANSFORMERS

If you have harmonics and/or high frequency transients, you may saturate the current carrying capacity of the transformer or it's magnetic core. Then the transformer will add additional harmonics and transients, and make the problem worse.

In addition, the transformer may blow up. A very expensive, bad and even dangerous thing. Plus, when a transformer blows up, the engineer who specified it usually gets fired.

Harmonic Mitigating Transformers (HMTs) are very good ideas if a lot of harmonics or transients are to be expected.

----

RETURN WIRE BREAKS

For these reasons, most though not all electrical problems occur on return wires. Neat!

Suppose a return wire connection breaks in a multi-phase electric system. Now consider the voltage in return wire in the circuits after the break. It isn't supplied from the pole or ground. It is created by looking at the local loads as voltage dividers - so the voltage in 125 V circuits can be substantially lower or higher than expected, damaging appliances.

Wow, what a neat idea! But not good from a maintenance, safety and liability perspective.

BTW, return wire breaks and voltage drops can occur at the pole or in the overhead lines too. If motors ever run slow or won't start, turn them off, or they may burn out!

----

GROUNDING

The NEC requires that electricians try to ground the return wire. But if they fail a certain number of times, they are allowed to stop trying. (Did I mention that the NEC is a very complex legal document, with exceptions and exceptions to exceptions to rules scattered all over the document, and that very few people can figure it all out?)

In addition, grounding strongly attracts lightning. A lightning strike can cause the ground around the grounding rod to melt, which destroys or weakens the ground connection.

I'm not sure what this all means to good building design. But you can't rely on a good electrical ground.

NEC requires most antennas to be grounded - but this rule is ignored by many antenna installers. A big potential problem, if hit by lightning.

Local state and local laws often contain exceptions to the NEC (which is created by Underwriter's Laboratories, and is not required by Federal Law). For example, high lightning incidence states and counties frequently bar grounding, and may bar or make lightning rods optional, to prevent fires and appliance damage caused by lightning strikes. Alas, this is not always done at local high incidence points in other states and counties, such as on top of hills or over ground with conductive ores.

If you do have a lightning strike on a grounded lightning rod or antenna, it is an extremely good idea for the rod to be outside the main roof area, and for the wire to ground to be straight - else the current may jump the wire and cause fires or other problems. This may be part of NEC - I'm not sure.

----

TRYING TO SAVE LIGHTING ENERGY - badly

Some people think that if you take out every other flourescent light bulb you save energy. But if the ballast requires a balanced load between two bulbs, it will stay in start mode. This burns out the bulb or ballast, and consumes more energy.

The same is true if you remove both flourescent bulbs. If you want to cut power, remove the ballast, not the bulb.

TRYING TO INCREASE LIGHT BULB LIFETIME - badly

If you never switch most types of light bulb off, they last many times longer. This makes sense if the greater cost is from replacing bulbs - as is often true, if you need to hire an expert to do it. But if the greater cost is from electricity, it's cheaper to replace the bulb.

An interesting alternative is LED lighting - which consumes less current for a given luminance level, yet lasts longer. But you have to trade off the higher initial cost. Note that the lower heat load also lowers refrigeration costs on the rink. It also reduces mold problems next to warm light bulbs.

FIRE

Fire is bad. It is a health and safety problem, creating high liabilities. It is also a substantial economic cost in of itself.

Non-flammable and reduced flammability building materials and upholstry can make a big difference.

For example, drywalls differ in flammability.

Some paints are non-flammable. Some, like many oil and latex paints, are highly flammable. Pay attention.

BTW, if both sides of a piece of wood are painted with outdoor or latex (sealed) paints, the wood will likely rot from within, because it can't breath and dry.

VENTILLATION

Many buildings have furnace hot air ducts located near the floor. The idea is that heat rises, so this will naturally create circulation patterns, and warm the whole room.

Many buildings use the same ducts for air conditioning. Not so good. The floor stays cold. You need a lot of extra energy to make the whole room cool.

Ceiling fans can help circulation a lot.

Of course, be careful around the ice rink itself. You don't want circulation patterns to mix the cold air next to the ice with the warmer air above it.

[Query]

EXTRA IDEAS

Have many places to throw things out, so people won't litter. Especially in bathrooms, where some people will flush things down the toilet that don't belong there if they can't find an adequate alternative.

Just as over-sized wires lead to fewer electrical problems, so do over-sized water pipes. You also want to avoid sharp curves in pipes. That includes bends, and it includes plumbing traps.

Don't ask me why, but to many people vandalism, especially of plumbing fixtures, is considered fun. Try to make them difficult to vandalize. Faucets should turn themselves off. Use tamper resistant bolts and screws.

Vandalism seems to be more common in places that males go, like male dressing rooms and rest rooms. But don't presume that young males won't consider it fun to sneak into places that females go to create similar problems.

Some public buildings use direct-flush toilets. Ideally you should augment water pressure using pumps. They flush faster, use less water, and are literally orders of magnitude less likely to develop clogs.

If male attended places have more vandalism, female attended places develop far more plumbing clogs. Some people say this is caused by feminine hygiene products, which most modern plumbing systems do not handle well. In principle, they could be discarded in a waste basket. Use a covered basket, and use plastic bags so the sides of the basket don't get contaminated. Perhaps a sign would help.

[Query]

EDIT: I should have said my expert had an "unlimited masters license" not a "general masters license".

In addition:

The fix to the excess RMS current on the neutral wires problem is that, in those cases where there are a significant number of electronic devices, UPS [Uninterruptible Power Supply] devices, or lighting ballasts on circuits, the neutral wire should be rated to twice the current capacity of the hot wires.

The fix to the underestimation of RMS current is to use RMS-responding breakers instead of mean responding breakers, for those circuits.

Note that the NEC mentions compensating for non-linear load, but makes no explanations. Therefore most electricians, even master electricians, do not understand the issues, and have never heard of "harmonics" or "transients". The building engineer must clarify, and must specify the solutions. Best practice is for the building engineer to interface personally to the master electrician overseeing any installation job, something rarely done. Best practice is also for the master electrician to supervise on-site during all installations, rather than sit back in the shop office and let apprentices do all the work, as is done in most shops.

Note also that the best HMTs do several things differently than regular transformers: the neutral wire should be able to carry double the RMS current load of the hot wires, the magnetic core should be able to carry the excess load too, the phases should be slightly off (i.e., not exactly 1/180 second apart) so harmonics don't add up as completely, and the transformer should tend to filter current to 60 Hz.

The correct fix for problems that occur when multiple filters (such as ballast filters in internal lighting and outdoor electric pole filters) are resonant is probably to test for such resonance, but my expert says that the most common solution is that the electric replaces the outdoor pole filter with a different frequency after it burns out, on the assumption that the electricians and building engineers for the building won't understand the problem.

Some building engineers or master electricians simply overbuild, by specifying a over-sized transformer. My electrician expert says this often fails in the end - because future electricians will see the excess capacity, and will take advantage of it. In addition, it does nothing to filter out the harmonics that can damage various appliances. (E.g., motors are particularly susceptible to heating from 5th harmonics; three phase circuits are particularly susceptible to damage from 3rd and other triplet harmonics; inductive heating problems come from all harmonics, but are worst for higher harmonics.)

----

Many ice rinks suffer glass breakage around the rink, due to fast moving hockey pucks. Some of the rinks near me have been substituting Plexiglas for glass after each breakage. Maybe it would make sense to install Plexiglas in the first place? I'm uncertain - Plexiglas is more expensive, and it scratches more easily.

Many rinks suffer lighting fixture breakage and speaker breakage from fast moving pucks too. It is probably best practice to have a grating to protect the fixtures and speakers - though that slightly reduces lighting and sound efficiency.

I have polished scratched eyeglasses with mild abrasives like toothpaste to remove scratches. I wonder if that is practical for Plexiglas...? I wonder if the replacement of glass by Plexiglas in my local rinks is more a health and safety issue than a cost issue... Don't know.

Some rinks use very high ceilings to avoid breakage, but I've been told that isn't completely effective, and is sometimes expensive in of itself. A local curling club saved money by having low ceilings, lit by unshielded lighting - but they disallow hockey. In fact, they say the floor is not sturdy enough for any type of skating, so you can't figure skate on their ice surface either.

There are ways to build relatively inexpensive high ceiling "bubble" construction buildings. But climate control costs are likely to be high. I'm not sure where the trade-off's occur.

----

[VAsk8r]

Most of the rinks where I skate don't use ice monitors unless it's a really crowded public. I assume this is an attempt to save money, but I wonder if it really costs more in the long run because of lost business. Are freestyle skaters the only ones annoyed by bad behavior at a public session? By bad behavior, I mean cutting through the center of the ice, playing tag, cutting people off, bouncing little balls on the ice, kicking around a hockey puck, skating in the wrong direction or other behaviors that might scare another skater, hurt another skater or generally create annoyance and chaos.

So I wonder if this kind of behavior makes some people not want to come back. On the other hand, if the people behaving badly were told they couldn't do any of that anymore, they might decide skating wasn't fun and also not come back.

Of course, that's not even getting into the potential liability risks. I'm told in Virginia, it's extremely hard to win a lawsuit if your injury was caused by your own bad behavior. But I imagine if you're injured by someone else, it's considerably easier. Most rinks display some kind of liability waiver, and mine gives you stickers that state by paying for public session, you're waiving liability. I don't know how well that holds up in court, though.

[sampaguita]

Our rink has one mega-public session, and only zambonis 3-4x (!) in a day: before opening the rink, 4 hours after, then another 4 hours after, then right before the hockey game, if there is one. They also don't use distilled water for the ice so the ice is always bad, except after zamboni. No ice monitors, too.