This table shows sand material specifications.
Link to this table
| Parameter | specification | Size | Notes |
|---|---|---|---|
| Sand | clean AASHTO M-6 or ASTM C-33 concrete sand | 0.02” to 0.04” | Sand substitutions such as Diabase and Graystone #10 are not acceptable. No calcium carbonated or dolomitic sand substitutions are acceptable. Rock dust cannot be substituted for sand. |
| Underdrain Gravel | AASHTO M-43 | 1.5” to 3.5” | |
| Geotextile Fabric (if required) |
ASTM D-4833 (puncture strength - 125 lb.) ASTM D-1117 (Mullen Burst Strength - 400 psi) ASTM D-4632 (Tensile Strength - 300 lb.) |
0.08” thick equivalent opening size of #80 sieve | Must maintain 125 gpm per sq. ft. flow rate. Note: a 4” pea gravel layer may be substituted for geotextiles meant to separate sand filter layers. |
| Impermeable Liner (if required) |
ASTM D-4833 (thickness) ASTM D-412 (tensile strength 1,100 lb., elongation 200%) ASTM D-624 (Tear resistance - 150 lb./in) ASTM D-471 (water adsorption: +8 to -2% mass) |
30 mil thickness | Liner to be ultraviolet resistant. A geotextile fabric should be used to protect the liner from puncture. |
| Under-drain Piping | ASTM D-1785 or AASHTO M-278 | minimum 4” rigid schedule 40 PVC | 3/8” perf. @ 6” on center, 4 holes per row; minimum of 3” washed #57 stone over pipes; not necessary underneath pipes |