HY8:Plastic Pipe Materials

HY-8 7.1 has been updated to incorporate different types of plastic pipes. The following types of plastic pipes and their associated inlet configurations have been added to HY-8 7.1:

1. PVC

a. Manning’s n (From HDS-5): 0.009-0.011 (use 0.011)

b. Inlet Configurations:

i. Square Edge with Headwall

1. Notes:

a. Use HY8 Equation Number 9

b. HDS5 Chart Number 1-1

c. Equation for Concrete Pipe Square Edge with Headwall

ii. Beveled Edge (1:1)

1. Notes:

a. Use HY8 Equation Number 6

b. HDS5 Chart Number 3-A

c. Equation for Circular pipe culvert with beveled edge (1:1)

iii. Beveled Edge (1.5:1)

1. Notes:

a. Use HY8 Equation Number 7

b. HDS5 Chart Number 3-B

c. Equation for Circular pipe culvert with beveled edge (1.5:1)

iv. Mitered to Conform to Slope

1. Notes:

a. Use HY8 Equation Number 2

b. HDS5 Chart Number 2-2

c. Equation for Corrugated Metal pipe culvert, Mitered to conform to slope

2. Smooth HDPE

a. Manning’s n (From HDS-5): 0.009-0.015 (use 0.012)

b. Inlet Configurations:

i. Square Edge with Headwall

1. Notes:

a. Use HY8 Equation Number 9

b. HDS5 Chart Number 1-1

c. Equation for Concrete Pipe Square Edge with Headwall

ii. Beveled Edge (1:1)

1. Notes:

a. Use HY8 Equation Number 6

b. HDS5 Chart Number 3-A

c. Equation for Circular pipe culvert with beveled edge (1:1)

iii. Beveled Edge (1.5:1)

1. Notes:

a. Use HY8 Equation Number 7

b. HDS5 Chart Number 3-B

c. Equation for Circular pipe culvert with beveled edge (1.5:1)

iv. Thin Edge Projecting

1. Notes:

a. Use HY8 Equation Number 1

b. HDS5 Chart Number 2-3

c. Equation for Corrugated Metal pipe culvert, Thin edge projecting

v. Mitered to Conform to Slope

1. Notes:

a. Use HY8 Equation Number 2

b. HDS5 Chart Number 2-2

c. Equation for Corrugated Metal pipe culvert, Mitered to conform to slope

3. Corrugated PE

a. Manning’s n (From HDS-5): 0.009-0.015 (use 0.024)

b. Inlet Configurations:

i. Square Edge with Headwall

1. Notes:

a. Use HY8 Equation Number 3

b. HDS5 Chart Number 2-1

c. Equation for Corrugated Metal pipe culvert with Headwall

ii. Beveled Edge (1:1)

1. Notes:

a. Use HY8 Equation Number 6

b. HDS5 Chart Number 3-A

c. Equation for Circular pipe culvert with beveled edge (1:1)

iii. Beveled Edge (1.5:1)

1. Notes:

a. Use HY8 Equation Number 7

b. HDS5 Chart Number 3-B

c. Equation for Circular pipe culvert with beveled edge (1.5:1)

iv. Thin Edge Projecting

1. Notes:

a. Use HY8 Equation Number 1

b. HDS5 Chart Number 2-3

c. Equation for Corrugated Metal pipe culvert, Thin edge projecting

v. Mitered to Conform to Slope

1. Notes:

a. Use HY8 Equation Number 2

b. HDS5 Chart Number 2-2

c. Equation for Corrugated Metal pipe culvert, Mitered to conform to slope