After reading many questions on the forums I wanted to post this as a future reference in order to help answer any basic questions regarding lighting. I work in the lighting industry and wanted to help as there seems to be many basic questions out there. In the future I am going to do a comparison of some of the various lighting fixtures available in the market.
First there are some basic lighting terms you must be familiar with to make the correct choice in lighting your table:
Watts: Wattage is a measure of electrical power used. It is a product of current and voltage. Sockets for fixtures will have a maximum lamp wattage rating which should not be exceeded. When manufacturers determine the maximum wattage on a socket it is due to the amount of heat the socket can handle. The amount of heat produced by a light source is directly proportional to the amount of watts drawn. Some sources are much more efficient than others so there will be less heat generated due to using a more efficient product and less watts. A 20 Watt Incandescent, 20 Watt LED, and 20 Watt CFL will all emit the same amount of heat. You should be able to use a lamp of less wattage however when starting with Incandescent.
Lumen: Lamps and LED fixtures have lumen ratings. A Lumen is the luminous intensity of amount of light emitted from the light source. Some sources are much more efficient in the amount of lumen's they can produce for a given amount of power. The term for this is lumen's per watt. For example a common replacement for a 100 Watt incandescent is a 25 Watt CFL. They both have around 1300 lumen's but CFL uses ¼ of the wattage. The incandescent in this case has 13 lumen's per watt and the CFL has 52 lumens per watt. Some newer LED fixtures have over 100 lumen's per watt! In addition to this the lumen's of lamps depreciate over time. For non-LED products there are two lumen ratings – intitial lumen's and mean lumen's. Use the mean lumen rating when choosing a product as these are the lumen's you will get for the majority of the product life. More on LED lumen losses later in this article.
Product Life: Non-LED product life has a B-50 rating. What this means is that the hours given are expressed as when on average half of the lamps are burned out and half are still working. On average a 20,000 hour rated fluorescent fixture will have half the lamps burned out at 20,000 burn hours. As a good practice usable life is around 75% to 80% of this rating. At that time it would be wise to change out all lamps due to decreased lumen's and the fact the lamps will in all probability soon fail. For LED the life given is a function as to when you will lose enough lumen's so you will need to replace them. This is expressed as an “L” rating. The most common is L70 @ a given amount of hours. As an example if you purchase a LED lamp with an L70 rating at 20,000 hours it means it will still be burning at 20,000 hours but only be at 70% of its rated lumen output and you may want to change as you have lost enough lumen's to warrant it.
CCT: Correlated Color Temperature. This is the rating to tell you if a lamp is warm or cold. The higher the color temperature is the cooler it is. Some common examples are:
2700K – Incandescent – Warm Colors (brings out reds and yellows)
4100K – Fluorescent – office Lighting (general lighting – brings out more blues)
6000K – Fluorescent or LED outdoor – Brings out the most blues - Daylight
There of course are many variations to this. Fluorescents and LED's are available in most of the common color temperatures. The choice of color temperature seems to vary greatly per individual.
CRI: CRI stands for color rendering index. A lamp with a high CRI renders colors more accurately than one with a low CRI. A perfect light source (incandescent or the sun) has a CRI of 100. In order for manufacturers to determine CRI they have their product tested against a perfect (100 CRI) reference source of the same color temperature. They test several pastel color chips against their lamp and for every visible color shift they subtract points. As a result there may be circumstances where a lamp has a good CRI rating but yet doesn't do so well showing a particular color. LED generally has not done well with Reds so the lighting so many manufacturers are starting to a R9 (Red) value in addition to CRI. For practical purposes in general lighting such as warehouses 70CRI is the standard. For retailers and more critical applications 80 or even 90 CRI are commonly used.
Foot Candles and Lux: Foot candles are the measurement of light hitting a work plane. One lumen hitting 1 square foot of work plane equals one foot candle. One foot candle hitting one square meter is 1 lux. The industry accepted calculation is that 10 Lux is equal to 1 foot candle. Many of the industry standards are published in lux so it is important to know both. Most of the published data I have found mentions 50 foot candles at the center of the table being the accepted amount of light for competitive billiards. That would mean a minimum of 1700 lumen's hitting the surface on a regulation table. You did notice I said that a foot candle is the amount of light hitting the surface? Depending on the design of the fixture the amount of light lost by the time it hits the table surface can vary greatly. A common fixture for billiards that I have seen has several incandescent lamps which not only direct light down to the table but also light a decorative glass side. I would approximate up to 50% of the lumen's may be lost before they hit the table surface. A fluorescent or LED fixture with direct downward lighting may have 90% or more of the lumen's reaching the work plane.
Options for Existing Tables:
Incandescent: As mentioned earlier incandescents have the highest CRI. They will do the best job in bringing out the warmer colors. The downfall is that they are not very efficient and lose lumen's much quicker than other technologies. You can closely approximate how much it will cost to run a lamp by calculating $1 per watt if you burned the lamp 24/7 all year. If you averaged three hours a day and had three 150 watt lamps in your fixture it would cost less than $60 per year. You will probably need to change the lamps at least twice per year as incandescents are normally only rated at 1000 hours (half will be burned out at 500 hours) and light output will diminish quickly within a couple hundred burn hours. A better answer may be a CFL or LED lamp with a high CRI. Lamps that are energy star rated have some standards required by the Department of Energy in regards to efficiency and color consistency so I would use that a minimum standard when choosing products. LED lamps are getting very close in price to CFL's so I personally may lean that way. Just be careful to make sure it has a decent R9 value and that it is omni-directional if your existing fixture has a standard A lamp which also emits lumen's in all directions (for up light and/or lighting the sides of the fixture). If your fixture has a different incandescent you are supposed to use for it (such as a directional Par lamp) there are LED replacement lamps for almost all of these.
Fluorescent: If your existing fixture has T12 lamps (the fat tubes) I would convert to a T8 system. You generally just need to replace the ballast and lamps and you are good to go. If you have existing T8 lamps there have been some good improvements in recent years. There are T8 lamps now with 65,000
hour lives (half are burned out at 65,000 hours). Playing 3 hours a day 365 days per year these will last many of us a lifetime. The newer fluorescents also have improved lumen performance and CRI. In a fluorescent system the weak point is the ballast. If the ballast came with the fixture or if you purchased a cheap one from a home store I would recommend spending $20 - $30 to get a good ballast. These are more efficient and will save you money due to electricity savings. Also I have personally experienced 20% additional lumen's out of the fixture by changing the factory ballast. Many fixture manufacturers buy the least expensive ballast they can to keep cost down. Even if the existing ballast is a brand name it may be their cheap OEM line used to compete on bids with the offshore stuff. I would check with a local electrical supply house to see if you need an upgrade.
LED tubes are now starting to be the rage. As mentioned above there are fluorescent systems close to the life at a fraction of the cost. If you do want to use an LED tube I would recommend the ones where you purchased a dedicated driver to replace the existing fluorescent ballast. As mentioned before the ballast is the weakest part of the system and the Led tubes that are made to run with a dedicated driver seem to perform better.
New Fixtures: Besides the fixtures mentioned above LED's are now the rage. They vary greatly in quality due to the influx of offshore companies capitalizing on the trend. I will be comparing some of these in a future post. For now if you see a fixture you like but are unsure of the company making it I would recommend you purchase a product that is Design Lights Consortium approved. Like energy star this testing is done through the department of energy to make sure a basic standard is met. I have seen many fixtures claim to be DLC certified on their web page only to find they are not. To be sure you can search the qualified product list at https://www.designlights.org/QPL
More to come....
First there are some basic lighting terms you must be familiar with to make the correct choice in lighting your table:
Watts: Wattage is a measure of electrical power used. It is a product of current and voltage. Sockets for fixtures will have a maximum lamp wattage rating which should not be exceeded. When manufacturers determine the maximum wattage on a socket it is due to the amount of heat the socket can handle. The amount of heat produced by a light source is directly proportional to the amount of watts drawn. Some sources are much more efficient than others so there will be less heat generated due to using a more efficient product and less watts. A 20 Watt Incandescent, 20 Watt LED, and 20 Watt CFL will all emit the same amount of heat. You should be able to use a lamp of less wattage however when starting with Incandescent.
Lumen: Lamps and LED fixtures have lumen ratings. A Lumen is the luminous intensity of amount of light emitted from the light source. Some sources are much more efficient in the amount of lumen's they can produce for a given amount of power. The term for this is lumen's per watt. For example a common replacement for a 100 Watt incandescent is a 25 Watt CFL. They both have around 1300 lumen's but CFL uses ¼ of the wattage. The incandescent in this case has 13 lumen's per watt and the CFL has 52 lumens per watt. Some newer LED fixtures have over 100 lumen's per watt! In addition to this the lumen's of lamps depreciate over time. For non-LED products there are two lumen ratings – intitial lumen's and mean lumen's. Use the mean lumen rating when choosing a product as these are the lumen's you will get for the majority of the product life. More on LED lumen losses later in this article.
Product Life: Non-LED product life has a B-50 rating. What this means is that the hours given are expressed as when on average half of the lamps are burned out and half are still working. On average a 20,000 hour rated fluorescent fixture will have half the lamps burned out at 20,000 burn hours. As a good practice usable life is around 75% to 80% of this rating. At that time it would be wise to change out all lamps due to decreased lumen's and the fact the lamps will in all probability soon fail. For LED the life given is a function as to when you will lose enough lumen's so you will need to replace them. This is expressed as an “L” rating. The most common is L70 @ a given amount of hours. As an example if you purchase a LED lamp with an L70 rating at 20,000 hours it means it will still be burning at 20,000 hours but only be at 70% of its rated lumen output and you may want to change as you have lost enough lumen's to warrant it.
CCT: Correlated Color Temperature. This is the rating to tell you if a lamp is warm or cold. The higher the color temperature is the cooler it is. Some common examples are:
2700K – Incandescent – Warm Colors (brings out reds and yellows)
4100K – Fluorescent – office Lighting (general lighting – brings out more blues)
6000K – Fluorescent or LED outdoor – Brings out the most blues - Daylight
There of course are many variations to this. Fluorescents and LED's are available in most of the common color temperatures. The choice of color temperature seems to vary greatly per individual.
CRI: CRI stands for color rendering index. A lamp with a high CRI renders colors more accurately than one with a low CRI. A perfect light source (incandescent or the sun) has a CRI of 100. In order for manufacturers to determine CRI they have their product tested against a perfect (100 CRI) reference source of the same color temperature. They test several pastel color chips against their lamp and for every visible color shift they subtract points. As a result there may be circumstances where a lamp has a good CRI rating but yet doesn't do so well showing a particular color. LED generally has not done well with Reds so the lighting so many manufacturers are starting to a R9 (Red) value in addition to CRI. For practical purposes in general lighting such as warehouses 70CRI is the standard. For retailers and more critical applications 80 or even 90 CRI are commonly used.
Foot Candles and Lux: Foot candles are the measurement of light hitting a work plane. One lumen hitting 1 square foot of work plane equals one foot candle. One foot candle hitting one square meter is 1 lux. The industry accepted calculation is that 10 Lux is equal to 1 foot candle. Many of the industry standards are published in lux so it is important to know both. Most of the published data I have found mentions 50 foot candles at the center of the table being the accepted amount of light for competitive billiards. That would mean a minimum of 1700 lumen's hitting the surface on a regulation table. You did notice I said that a foot candle is the amount of light hitting the surface? Depending on the design of the fixture the amount of light lost by the time it hits the table surface can vary greatly. A common fixture for billiards that I have seen has several incandescent lamps which not only direct light down to the table but also light a decorative glass side. I would approximate up to 50% of the lumen's may be lost before they hit the table surface. A fluorescent or LED fixture with direct downward lighting may have 90% or more of the lumen's reaching the work plane.
Options for Existing Tables:
Incandescent: As mentioned earlier incandescents have the highest CRI. They will do the best job in bringing out the warmer colors. The downfall is that they are not very efficient and lose lumen's much quicker than other technologies. You can closely approximate how much it will cost to run a lamp by calculating $1 per watt if you burned the lamp 24/7 all year. If you averaged three hours a day and had three 150 watt lamps in your fixture it would cost less than $60 per year. You will probably need to change the lamps at least twice per year as incandescents are normally only rated at 1000 hours (half will be burned out at 500 hours) and light output will diminish quickly within a couple hundred burn hours. A better answer may be a CFL or LED lamp with a high CRI. Lamps that are energy star rated have some standards required by the Department of Energy in regards to efficiency and color consistency so I would use that a minimum standard when choosing products. LED lamps are getting very close in price to CFL's so I personally may lean that way. Just be careful to make sure it has a decent R9 value and that it is omni-directional if your existing fixture has a standard A lamp which also emits lumen's in all directions (for up light and/or lighting the sides of the fixture). If your fixture has a different incandescent you are supposed to use for it (such as a directional Par lamp) there are LED replacement lamps for almost all of these.
Fluorescent: If your existing fixture has T12 lamps (the fat tubes) I would convert to a T8 system. You generally just need to replace the ballast and lamps and you are good to go. If you have existing T8 lamps there have been some good improvements in recent years. There are T8 lamps now with 65,000
hour lives (half are burned out at 65,000 hours). Playing 3 hours a day 365 days per year these will last many of us a lifetime. The newer fluorescents also have improved lumen performance and CRI. In a fluorescent system the weak point is the ballast. If the ballast came with the fixture or if you purchased a cheap one from a home store I would recommend spending $20 - $30 to get a good ballast. These are more efficient and will save you money due to electricity savings. Also I have personally experienced 20% additional lumen's out of the fixture by changing the factory ballast. Many fixture manufacturers buy the least expensive ballast they can to keep cost down. Even if the existing ballast is a brand name it may be their cheap OEM line used to compete on bids with the offshore stuff. I would check with a local electrical supply house to see if you need an upgrade.
LED tubes are now starting to be the rage. As mentioned above there are fluorescent systems close to the life at a fraction of the cost. If you do want to use an LED tube I would recommend the ones where you purchased a dedicated driver to replace the existing fluorescent ballast. As mentioned before the ballast is the weakest part of the system and the Led tubes that are made to run with a dedicated driver seem to perform better.
New Fixtures: Besides the fixtures mentioned above LED's are now the rage. They vary greatly in quality due to the influx of offshore companies capitalizing on the trend. I will be comparing some of these in a future post. For now if you see a fixture you like but are unsure of the company making it I would recommend you purchase a product that is Design Lights Consortium approved. Like energy star this testing is done through the department of energy to make sure a basic standard is met. I have seen many fixtures claim to be DLC certified on their web page only to find they are not. To be sure you can search the qualified product list at https://www.designlights.org/QPL
More to come....
