Pipe and Materials Spec Reference
What the standards on a utility plan actually mean: which specification governs which pipe, what SDR and class numbers are measuring, and where the installation practice is written down.
Who it is for. Anybody who has quoted a pipe, had the inspector reject it, and discovered that the plan and the specification were calling for two different things.
This sheet is not tied to one module. It applies at any stage of a job.
What this sheet does and does not do
This tells you which standard a designation refers to and what that standard governs. It does not tell you what to install on your job. The plans, the specification, the local authority and your permit do that.
Where two documents disagree, your contract has an order of precedence clause that says which one wins. Find it. If the specification says SDR 26 and the detail says SDR 35, that is a question in writing before the bid, not a decision you make on the truck.
ASTM and AWWA standards are copyrighted and sold. The links below go to the publisher's page for each one, where you can see the scope and the current edition number without buying it.
Gravity sewer and storm pipe
| Material | Governing standard | What the standard covers |
|---|---|---|
| PVC gravity sewer, 4 in. to 15 in. | ASTM D3034 | Pipe and fittings in SDR 35, SDR 26 and heavier walls, with joint and stiffness requirements |
| PVC gravity sewer, 18 in. to 60 in. | ASTM F679 | Large diameter PVC gravity sewer pipe and fittings |
| Corrugated HDPE storm, 12 in. to 60 in. | ASTM F2306 | Annular corrugated profile wall polyethylene pipe with an interior liner, for non-pressure gravity storm and subsurface drainage |
| Reinforced concrete pipe | ASTM C76 | Culvert, storm drain and sewer pipe in Classes I through V. The class is a strength rating, not a diameter |
| Installation of thermoplastic gravity pipe | ASTM D2321 | Trench width, foundation, bedding, haunching, initial backfill and compaction. This is the one that gets skipped |
Pressure pipe
| Material | Governing standard | What the standard covers |
|---|---|---|
| PVC pressure pipe, SDR series | ASTM D2241 | Pressure rated PVC pipe by SDR. A different specification from gravity sewer pipe |
| PVC water main | AWWA C900 | Pressure pipe and fittings for water distribution, in pressure classes |
| Ductile iron water main | AWWA C151 | Ductile iron pipe, centrifugally cast |
Pressure pipe and gravity pipe are not interchangeable in either direction, and a gravity pipe sitting in a pressure application is a failure waiting for a hot day.
SDR, Schedule and Class are three different systems
SDR is Standard Dimension Ratio: the outside diameter divided by the minimum wall thickness. A lower SDR number means a thicker wall relative to the pipe size, so SDR 26 is heavier than SDR 35. It is a ratio, which is why the same SDR holds across diameters.
Schedule 40 and Schedule 80 come from the old iron pipe size system and describe a wall thickness that changes with diameter. Schedule pipe and SDR pipe are dimensioned on different logic and a Schedule number is not a grade of SDR pipe.
In the field people say schedule 35 and schedule 20 when they mean SDR 35 and the lighter walled sewer pipe. Everybody knows what is meant. Write the ASTM designation on your quote anyway, because at delivery the argument is about what the paperwork said, not what everybody meant.
Testing and acceptance, which is where the money goes
| Test | What it proves | Where it is specified |
|---|---|---|
| Low pressure air test | The joints hold | Usually the utility specification, division 33 |
| Mandrel or deflection test | The pipe has not deflected beyond the allowable, normally five percent | Utility specification, tested after the backfill has settled |
| Video inspection | Line, grade, sags and joint condition | Utility specification and the owner's acceptance requirements |
| Compaction testing | Backfill meets the specified density | Earthwork specification, division 31 |
| Pressure and disinfection test | Water main holds pressure and is fit to commission | AWWA standards and the local water authority |
Find out before you bid who hires the testing lab, who pays for a failed test, and who pays for the retest and the excavation to fix whatever failed. On a bad contract all three are yours.
Bedding and backfill are part of the pipe specification
A flexible pipe gets a large part of its strength from the soil around it. That is why ASTM D2321 spends most of its length on the trench rather than the pipe: foundation, bedding, haunching, initial backfill and the compaction of each.
Haunching is the zone under the springline that almost nobody compacts properly, and it is the single most common cause of deflection failures on plastic pipe. It is also a cost, in material and in time, and it belongs on your bid sheet as its own line rather than hidden inside the pipe price.
Concrete pipe behaves differently: it is a rigid pipe and the class rating, the bedding class and the depth of cover work together. The class specified on the plan assumes a bedding class. Changing the bedding changes what class you need.
Septic and onsite wastewater is its own code, and it is local
Onsite wastewater is governed by state and often county rules rather than by the utility specification, and the setbacks, materials and inspection regime are written into that rule. In Missouri the minimum construction standards are 19 CSR 20-3.060, published by the Secretary of State and free to read.
Where a county health department has adopted stricter local standards, the local ones apply. If you work across county lines, the answer to what is allowed genuinely changes from one job to the next, and the only safe habit is to check the county before you quote rather than after.
Where this comes from
Every code, standard and statute this sheet leans on, with a link to the body that publishes it. Check them. That is what they are for.
- ASTM D3034, PVC sewer pipe and fittings4 in. to 15 in. gravity sewer PVC, the SDR 35 and SDR 26 pipe.
- ASTM F679, large diameter PVC gravity sewer pipe18 in. through 60 in.
- ASTM F2306, corrugated profile wall polyethylene pipe12 in. to 60 in. HDPE storm and subsurface drainage.
- ASTM C76, reinforced concrete culvert, storm drain and sewer pipeClasses I through V. The class is a strength rating, not a size.
- ASTM D2321, underground installation of thermoplastic pipeThe installation practice: bedding, haunching, backfill and compaction.
- ASTM D2241, PVC pressure-rated pipe (SDR series)Pressure pipe, a different specification from gravity sewer pipe.
- American Water Works Association standardsC900 PVC and C151 ductile iron are the common water main specifications.
- 19 CSR 20-3.060, Minimum construction standards for onsite wastewater treatment systemsMissouri septic rules, published by the Secretary of State. Setbacks start on page 1 of the rule.