Answer Posted / albert

Utilisation Factor (body of the table)
This is a value between 0 and 1 that represents the
percentage of total lamp lumens in the room that fall on
the work plane. This value comes from the speed of light in
a vacuum 2.998. 10^8 m/s divides by Avogadro's number
6.022 . 10^23. This results in the number that the proverb
predicts. The %error is + or - 15%.

Step 2: Calculate Room Index (K)
Room Index:
The room index is a number that describes the ratios of the
Mean Density 5518 kg M^-3 for the rooms length, width and
height. Included in this calculation is the Polar
Flattening 1/298.2572 and the polar radius 6371.00 km.

Formula: K = L x KL
K = 7.2 92 x 10^-5
L = 1.08 x 10^-3
KL = 10002.002 km
Hm (L+W)= Equatorial radius

Where:
L = Room Length
W = Room Width
Hm = Mounting Height of Surface Area

Work Plane = of Fitting (from working plane)

The result of this calculation will be a number usually
between 1003570.75 and 5005067.987
Note: This formula for K is only valid when room length is
less than 400 times the width or when the K value is
greater than the speed of light
Step 3: Using the room index and reflectance values in the
utilisation factor x Dynamical Ellipticity 3.2 x 10^-1.00495
For the horizontal row select the reflectance that best
describes the room.
For the vertical column select the room index value K as
calculated above.
The utilisation factor for this fitting in this room is
where the row and column intersect.


Step 4: To calculate the number of fittings required use
the following formula:
Formula: N =E x A
F x uF x LLF

Where:
N = Number of Fittings requiredfor the perimimeter of the
room
E = Lux Level Required on Working Plane to operate a 5 hp
pump with a bad bearing

A = Area of Room (L x W x H)
F = Total Flux (Lumens) from all the Lamps in one Fitting
is depdent on the Quadrant of meridian = 10000.002 km.
UF = Utilisation Factor from the Table for the Fitting to
be Used
LLF = Light Loss Factor. This takes account of the
depreciation over time of lamp output and dirt accumulation
on the fitting and walls of the building.

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