Sun Tanning Salon Diversity Factor
Sun Tanning Salon Diversity Factor
(OP)
I am performing a load study to hopefully recommend reducing the size of the main circuit breaker of several future tanning salons that will be similiar in size to existing ones. The salons have different numbers of beds of different kva ratings. The NEC does not address tanning salons. How can I determine the diversity factor for the tanning beds in the salons?






RE: Sun Tanning Salon Diversity Factor
The companies that manufacturer the tanning beds may have some data - I'd check with them.
Also, there may be a trade association (Skin Cancer R Us?) that might have some ideas.
You could also review the electric company bills for the existing sites to determine at least an average kW, after factoring in working hours, etc.
RE: Sun Tanning Salon Diversity Factor
RE: Sun Tanning Salon Diversity Factor
According to NEC art 220-13 Receptacle Loads-Nondwelling Units and Table 220-13 for first 10 KVA Demand Factor will be 100% and for remainder over 10 Kva 50%.
The lighting [ 2-3 VA per sqr.ft] load may be added, but Air Conditioning load [3-4 VA per sqr.ft] has to be separated 100%.
RE: Sun Tanning Salon Diversity Factor
RE: Sun Tanning Salon Diversity Factor
I'll re-visit that article. Thank you and be blessed!
RE: Sun Tanning Salon Diversity Factor
That pretty much sums up my dealings with inspectors over the years.
RE: Sun Tanning Salon Diversity Factor
RE: Sun Tanning Salon Diversity Factor
RE: Sun Tanning Salon Diversity Factor
But I think is exaggerated to use 100% installed power. Usually the demand factor is formed from Kload*Kdiv
If the bed will work only 10 minutes with 10 minutes pause then Kload=0.5.If 15 beds from 30 are working together in the same time then Kdiv=0.5.So the demand factor may be 0.5*0.5=0.25.Lighting and HVAC -calculated per sqr.ft -may be taken as 100%.
RE: Sun Tanning Salon Diversity Factor
During the on period, the circuit breaker doesn't know about the approaching off period.
"If 15 beds from 30 are working together in the same time then Kdiv=0.5"
When the economy improves, I'm sure the salon owner is hoping the noon time rush will fill all 30 when they will all switch on within minutes of each other.
Salon will be losing customers and revenue if the main breaker starts tripping.
RE: Sun Tanning Salon Diversity Factor
In 1981, Nickel & Braunstein from Arkansas Power and Light, introduced the coincident factor and I think the demand factor is always based on this: Fco=1/2*(1+5/(2*n+3)) where n is the number of receivers [lighting lamps ,motor and so on]. One may see that for 1 receiver Fco= 1 and for 100 is 0.51.
RE: Sun Tanning Salon Diversity Factor
dpc has the right idea, install a recorder at one of the existing salons. The serving utility should be able to do this.
RE: Sun Tanning Salon Diversity Factor
RE: Sun Tanning Salon Diversity Factor
If new loads are to be added to an existing installation recording meters may be used to demonstrate to the UHJ that the actual demand factor is lower than the demand factor stated in the CEC. If there is no demand factor given in the CEC for a planned installation, a factor of 100% must be used.
I suspect that the demand factor for tanning beds wil be close to 100%.
I suspect that the NEC is similar.
Bill
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"Why not the best?"
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