What is the point by point method in illumination?

A method to calculate the horizontal illuminance on a workplane within a space, as well as its uniformity. Only the direct illumination from the luminaires to the workplane is taken into account.

How do you calculate Utilisation factor for lighting?

Utilization Factor (UF) Maintenance Factor (MF) Equation for Required Illumination is. E = N (n x φ) x MF x UF / A.

What are the steps for outdoor lighting calculation?

Step 1: Determine foot-candle level from outdoor candle table below. Step 2: Determine square footage of area to be lighted (length x width). Step 3: Determine type of fixture to be used and proper mounting height. Step 5: Determine dirt depreciation factor of fixture from Light Depreciation Chart below.

How many lights do I need in a room?

As a handy rule of thumb, a sitting room or bedroom will generally require around 10-20 lumens per square foot, while a bathroom or kitchen will need a stronger level of lighting, at around 70-80 lumens per square foot. To work out the lumens you need, simply multiply the square footage of the room by this figure.

How many lumens is a watt?

On average, an incandescent bulb produces around 14 lumens per watt, compared to 63 lumens for energy saving compact fluorescents (CFL) and 74 for LED bulbs.

How is lumens lighting design calculated?

Calculation in 8 steps

1. Total wattage of fixtures: Total wattage of fixtures = Number of lamps x each lamp’s watt. Total wattage of fixtures = 2 × 32 = 64 Watt.
2. Lumen per fixtures. Lumen per fixtures = Lumen efficiency (Lumen per Watt) x each fixture’s watt. Lumen per fixtures = 85 x 64 = 5440 Lumen.
3. Number of fixtures.

What is the zonal cavity method?

In lighting design, the lumen method, (also called zonal cavity method), is a simplified method to calculate the light level in a room. The method is a series of calculations that uses horizontal illuminance criteria to establish a uniform luminaire layout in a space.

Which is mostly used for lighting calculation?

A number of methods have been employed for lighting calculations, among which may be mentioned: 1. Watts per Square Metre Method 2. Lumen or Light Flux Method 3. Point to Point or Inverse-Square Law Method.

How do you calculate lighting uniformity?

Thus, by using the formula, we can calculate U1 = Minimum / Average lux = 551 / 624 = 0.88, and U2 = Minimum / Maximum lux = 551 / 708 = 0.78. The maximum lighting uniformity is 1, which means the lux levels in all the sampling points are the same.

How is lighting design calculated?

The simple and basic approach for calculating the lighting requirement is to divide the total light requirement of the room by light output (lumen) provided by a single lamp….Space to Height ratio

1. Hm = Mounting height.
2. A = Total floor area.
3. N = No. of Luminaires.

How to calculate the point source of lighting?

Electric Lighting Calculations Moon and Six Pence—Bath, UK Task Lighting (point source or line source method) Ambient Lighting (lumen or zonal cavity method) Two kinds of calculations Point Source Method 2 Line Source Method Or LED tubes Find the illuminance from a point or line source… …need drawings… …measure D = 26 ft. and = 60º…

How is direct calculation used in site lighting?

Direct Calculation Method considers only light directly from luminaires to calculation points and is capable of point-by-point results only, it cannot be rendered. This method lends itself particularly well to exterior lighting projects such as site lighting, roadway and sports applications.

Which is an example of point by point lighting?

This example will consider the illuminance at a single point on a horizontal surface from a single luminaire straight down, given that: Calculate the illuminance level on this point. This tells us that 398 lux will strike the point in question directly from the luminaire and no reflected light is calculated.

What does 398 Lux mean in point by point lighting?

This tells us that 398 lux will strike the point in question directly from the luminaire and no reflected light is calculated. The answer is a maintained illuminance level since a light loss factor of 0.85 was included to account for the loss of light over time due to reduced lumen output of the lamp and dirt on the luminaire surfaces.