Hi there,
I was looking at the Pressure Relief Valve Engineering handbook for Anderson Greenwood, Crosby and Varec products, Technical publication No. TP-V300.
On pages 153 and 209 the coefficient C is calculated for both US and metric units respectively.
Even though the calculated values for C are correct on each plot, there is an error on the equation as printed on the page.
The error is in the equation where the k outside the square root should be inside the square root. It is the same error for both figures 7-30 and 8-30.
See equation 8 in ISO 4126-7
Many thanks
Gerard