Hi everyone,
I was calculating the critical valve closing time for a water hammer case using the Caesar manual formula, which is as under.

The speed of sound in the fluid can be estimated from
c = [Ef / (ρ + ρ(Ef / E) (d/t) )] 0.5
Where:
Ef - is the bulk modulus of the fluid (313000 psi)
E - is the modulus of elasticity of the pipe (30E6 psi)
d - is the pipe mean diameter
t - is the pipe wall thickness
ρ - is the fluid density (62.4 lbm/ft3)

Step 1:
ρ + ρ(Ef / E)(d/t) = 62.4 lbm/ft3 [1 + (313000/30E6) (8.625 -0.322)/0.322 ] = 79.1875 lbm/ft3

Step2:

c = (313000 lbf/ in2) (ft3/79.1875 lbm) (32.2 lbm ft/lbf sec2) (144in2 /ft2)1/2 = 4281 ft/sec

Now my query is.

In step 1 of calculation he is calculating as per the formula but in step 2 there is introduction acceleration due to gravity factor 32.2 lbm ft/lbf sec2 which does not figure anywhere in the formula for c given above.
Is the formula incorrect and if it correct why did he introduce this factor.