Corrosive Waste & Neutralization Solutions for Engineers with SMS

Chapter 1: Corrosive Waste Piping Systems

Key Takeaways:

1. Canadian code (OBC 2281) restricts corrosive waste piping materials to borosilicate glass, polyvinylidene fluoride (PVDF), and polypropylene.
2. CPVC does not satisfy the specific chemical resistance requirements for corrosive waste as per CSA B181.000.
3. Venting systems for corrosive waste must operate independently from standard DWV systems to avoid corrosion.

Chapter 2: Material Selection and Cost Considerations

Key Takeaways:

1. Borosilicate glass, while ideal for plenums and vertical shafts, is the only non-combustible option but is costly due to the specialized labor required.
2. Polypropylene is cost-effective but necessitates sprinkler systems in non-combustible buildings and cannot be utilized in vertical shafts.
3. PVDF meets flame and smoke requirements for non-sprinklered buildings but carries a higher cost compared to polypropylene.

Chapter 3: Neutralization Systems and Code Requirements

Key Takeaways:

1. The Canadian code (2444) requires neutralization or dilution tanks for discharge of corrosive waste, connected to the sanitary drainage system via traps or indirect connections.
2. Specific pH discharge limits set by municipalities necessitate neutralization prior to discharge; dilution alone may be inadequate or prohibited.
3. Neutralization methods can be passive (e.g., using limestone for acids) or active (e.g., injecting alkaline solutions), with tank sizing dependent on fixture units, flow rate, and dwell time.

Chapter 4: Neutralization Tank Design and Specification

Key Takeaways:

1. Passive neutralization systems using limestone require a minimum retention time of one gallon per hour per fixture unit, factoring in limestone volume for functional capacity.
2. Active systems involve pumps, agitators, and pH controllers, necessitating careful specification for proper sizing and functionality.
3. Submitted neutralization systems require scrutiny since they are engineered solutions lacking standardized compliance certifications.