Page 34 - CPVC Fire Sprinkler Products Installation Instructions & Technical Handbook
P. 34

Thermal Expansion – U.S. Units
TYCO CPVC Pipe, like all piping materials, expands and contracts with changes in temperature. The coefficient of linear expansion for TYCO CPVC Pipe is: 0.000034 in/in/°F. The coefficient of linear expansion TYCO CPVC Pipe is the same for all pipe sizes.
To determine the linear expansion of the pipe due to thermal changes use the following formula:
∆L = 12eL (∆T) Where:
e = 0.000034 in/in/°F (coefficient of linear expansion) L = Length of run in feet
∆T = Temperature change in °F
∆L = Inches
Example: How much will a 40 foot run of 3/4 inch TYCO CPVC Pipe increase in length (or expand) if the expected ambient temperature ranges from 35°F to 85°F? Changes in length due to fittings are insignificant relative to the pipe.
∆L = 12eL (∆T) ∆L=12(0.000034)x40x50
∆L = 0.82 inch or approximately 13/16 inch
TYCO CPVC exhibits a relatively high coefficient of thermal expansion. When designing TYCO sprinkler systems, expansion of long runs must be considered if temperature variations will be encountered (i.e., summer to winter extremes). Methods of compensating for thermal expansion are expansion loops, offsets and change of direction of the pipe run shown in Figure 7.
Loop Lengths “L” for use in Figure 7 are shown in Tables H1, J1, and K1. If the change in temperature and the maximum working temperature are lower than those used to derive the tables, the numbers will be conservative in nature. For example, for a temperature change from 60°F to 125°F use Table J1 because the maximum temperature is greater than those shown in Tables G1 and H1.
For conditions that are not covered in the Loop Length Tables, use the following formula:
L = Length of loop, offset, or charge of direction in inches
E = Modulus of elasticity at the maximum temperature (Table L1) in psi D = Nominal outside diameter of pipe (Table D1) in inches
∆L = Change in length of pipe due to change in temperature in inches S = Working stress at the maximum temperature (Table L1) in psi

   32   33   34   35   36