15.3 Special Wastes, Chemical Neutralization, and Health Care Drainage
Key Takeaways
- IPC 803.1 prohibits discharging corrosive liquids, spent acids or other harmful chemicals into the plumbing system without thorough dilution, neutralization or treatment by an approved device.
- IPC 803.1 requires the neutralizing device to be automatically provided with a sufficient supply of diluting water or neutralizing medium to make the contents noninjurious before discharge.
- IPC 803.2 requires chemical drainage and vent systems to be completely separated from the sanitary systems, with chemical waste not discharging to sanitary drainage until treated.
- IPC 901.3 requires the vent system for a chemical waste system to be independent of the sanitary vent system, terminating separately through the roof or to an ASSE 1049 air admittance valve.
- IPC 918.8 prohibits air admittance valves in nonneutralized special waste systems except where they comply with ASSE 1049, use materials approved under Section 702.5 and are tested for chemical resistance per ASTM F1412.
Corrosive and harmful wastes — IPC 803.1
Corrosive liquids, spent acids or other harmful chemicals that destroy or injure a drain, sewer, soil or waste pipe, or create noxious or toxic fumes or interfere with sewage treatment processes shall not be discharged into the plumbing system without being thoroughly diluted, neutralized or treated by passing through an approved dilution or neutralizing device. Such devices shall be automatically provided with a sufficient supply of diluting water or neutralizing medium so as to make the contents noninjurious before discharge into the drainage system. The nature of the corrosive or harmful waste and the method of its treatment or dilution shall be approved prior to installation.
Four separate requirements:
- Dilute, neutralize or treat before discharge.
- Use an approved dilution or neutralizing device.
- The device must be automatically supplied with diluting water or neutralizing medium — not manually charged.
- The nature of the waste and the treatment method must be approved before installation, not after.
Recall the target from IPC 803: the discharge must be rendered noninjurious. Practice in laboratory work is to neutralize to a pH between 6.0 and 8.0, using a limestone chip bed or a chemical dosing system.
Complete separation — IPC 803.2
A chemical drainage and vent system shall be designed and installed in accordance with this code. Chemical drainage and vent systems shall be completely separated from the sanitary systems. Chemical waste shall not discharge to a sanitary drainage system until such waste has been treated in accordance with Section 803.1.
Three code sections state the same principle from three directions:
| Section | Statement |
|---|---|
| 702.6 | Chemical waste shall discharge to a separate drainage system independent of the sanitary drainage system |
| 803.2 | Chemical drainage and vent systems shall be completely separated from the sanitary systems |
| 901.3 | The vent system for a chemical waste system shall be independent of the sanitary vent system |
Separation applies to the drain and the vent both. A chemical waste line that discharges to its own neutralizer but shares a vent with the sanitary system is non-compliant.
Chemical waste venting — IPC 901.3
The vent system for a chemical waste system shall be independent of the sanitary vent system and shall terminate separately through the roof to the outdoors or to an air admittance valve that complies with ASSE 1049. Air admittance valves for chemical waste systems shall be constructed of materials approved in accordance with Section 702.6 and shall be tested for chemical resistance in accordance with ASTM F1412.
IPC 918.8 states the prohibition from the AAV side: air admittance valves shall not be installed in nonneutralized special waste systems described in Chapter 8, except where such valves comply with ASSE 1049, are constructed of materials approved under Section 702.5, and are tested for chemical resistance per ASTM F1412.
Materials for chemical waste
Chemical waste piping comes from the chemically resistant rows of the Table 702.1 and Table 702.2 material lists:
| Material | Typical application |
|---|---|
| Polyolefin (polypropylene) | General laboratory acid waste |
| Polyvinylidene fluoride (PVDF) | High-purity and high-temperature laboratory waste |
| Borosilicate glass | Visible laboratory drainage where chemical resistance and inspection matter |
| Chemically resistant high-silicon cast iron | Heavy-duty industrial acid waste |
Joining follows the material-specific sections of IPC 705:
- 705.13 Polyolefin: heat-fusion joints, mechanical and compression sleeve joints.
- 705.14 PVDF: heat-fusion joints, mechanical and compression sleeve joints.
- 705.7 Borosilicate glass: caulked joints per the manufacturer.
- 705.16.6: borosilicate glass to other materials uses an approved adapter fitting.
Recall IPC 702.5: drainage piping receiving discharge above 140 degrees F must have a rated working temperature of not less than 180 degrees F. Laboratory and sterilizer waste routinely exceeds 140 degrees F.
Health care and special-function equipment
IPC 801.2 lists the special functions that require protection against backflow, flooding, fouling, contamination and stoppage: sterilization, humidification, distillation, processing, cooling, and storage of ice or foods.
The related health care requirements sit in Chapter 6 on the water side:
| Section | Requirement |
|---|---|
| 608.3.1 | Hospital fixture water supplies protected by an RPZ, an atmospheric or spill-resistant vacuum breaker assembly, or an air gap; bedpan washer hose vacuum breakers not less than 5 feet above the floor; hose connection vacuum breakers in health care or laboratory areas not less than 6 feet above the floor |
| 609.2 | Water service for Group I-2, Condition 2 facilities, with tracer wire for nonmetallic piping (609.2.1) |
| 609.5 | Prohibited water closet and clinical sink supply arrangements |
| 609.6 | Clinical, hydrotherapeutic and radiological equipment protection |
| 609.7 | Condensate drain trap seal |
| 609.8 | Valve leakage diverter |
On the drainage side, IPC 915.1 prohibits a combination waste and vent system from receiving the discharge from a clinical sink — a clinical sink carries the same waste as a water closet and needs conventional venting.
Other special wastes
| Waste | Requirement | Section |
|---|---|---|
| Condensate from fuel-burning appliances and cooling coils | Collected and discharged to an approved plumbing fixture or disposal area; corrosion-resistant piping not smaller than the appliance drain connection; horizontal slope not less than 1/8 inch per foot | 314 |
| Swimming pool wastewater, filter backwash and deck drains | Air gap indirect waste | 802.1.4 |
| Sterilizers and relief valves discharging potable water | Air gap indirect waste | 802.1.3 |
| Process tanks, filters, drips, boilers discharging nonpotable water | Air break or air gap | 802.1.5 |
| Industrial wastes to the public sewer | Not introduced until the code official or other authority determines no damage to the sewer or interference with the treatment plant | 302.2 |
| Detrimental materials — ashes, cinders, rags, flammable, poisonous or explosive liquids or gases, oil, grease | Shall not be deposited into the building drainage or sewer system | 302.1 |
Designing a laboratory waste system
A university teaching laboratory has twelve fume-hood sinks and two floor sinks, discharging dilute acids.
| Decision | Requirement | Section |
|---|---|---|
| Drainage system | Completely separate from the sanitary system | 702.6, 803.2 |
| Piping material | Polyolefin or PVDF from Tables 702.1 and 702.2, heat-fusion joints | 702.1, 705.13, 705.14 |
| Temperature rating | 180 degrees F if discharge exceeds 140 degrees F | 702.5 |
| Treatment | Approved dilution or neutralizing device, automatically supplied with neutralizing medium; the waste nature and treatment method approved before installation | 803.1 |
| Discharge point | To sanitary drainage only after treatment | 803.2 |
| Vent system | Independent of the sanitary vent; terminates separately through the roof or to an ASSE 1049 AAV of approved chemical-resistant materials tested to ASTM F1412 | 901.3, 918.8 |
| Laboratory faucets | Laboratory faucet backflow preventer (ASSE 1035, CSA B64.7) | Table 608.1 |
| Hose connections in the lab | Vacuum breakers not less than 6 feet above the floor | 608.3.1 |
| Traps | Chemical-resistant; drum traps serving chemical waste systems are permitted | 1002.3 exception |
| Emergency shower and eyewash | Colorado exempts emergency showers from the 421.8 shower valve location rule; the model IPC treats the fixture per Chapter 4 | 421.8 (CO) |
What does IPC 803.1 require of a neutralizing device serving corrosive laboratory waste?
How must a chemical waste vent system terminate under IPC 901.3?
Which drainage system arrangement does IPC 803.2 require for chemical waste?
Condensate piping from a fuel-burning appliance must have what minimum slope under IPC 314.1?