How can I apply the principle of equivalent facilitation to the placement or intensity of visual alarm strobes?
The current ADAAG requirement is for a minimum 75 candela strobe to provide sufficient illumination in all directions in the horizontal plane 50 feet from the strobe. The formula I1 divided by D1 squared = I2 divided by D2 squared can be used, where • I1 = 75 candela • D1 = 50 feet • I2 = new intensity • D2 = new distance If the strobe is to be mounted above 80 inches, calculate the new distance (D2) by the Pythagorean Theorem where the new distance is the hypotenuse of a triangle with 50 feet as its long leg and the height above 80 inches as its short leg. While strobes of intensity lower than 75 candela can work for rooms smaller than 50 feet, one should not place multiple, unsynchronized strobes in a room or space less than 80 feet across since the resulting composite flash frequency from multiple strobes may exceed the safe limits and trigger some types of epilepsy. Use the least number of strobes and lowest intensity needed to cover a space.
