IPC Section 803.2 / FDA GRAS Classification
What it means on the job
Propylene glycol is classified by the FDA as 'generally recognized as safe' (GRAS) and is non-toxic, unlike ethylene glycol which is hazardous to humans and animals. The IPC permits discharge of non-toxic substances to the sanitary drain system. Propylene glycol solutions at typical concentrations used in HVAC systems (25-50%) are biodegradable and do not pose a toxicity hazard to municipal wastewater treatment processes. However, contractors should always verify local sewer use ordinances, as some jurisdictions impose biochemical oxygen demand (BOD) limits that may require dilution or metered discharge of large volumes. For most routine system flushes of this volume, sanitary drain disposal of propylene glycol is code-compliant.
Tested in 1 CraftIQ puzzle
- code-checkPropylene Glycol Drain Disposal
Related IPC sections
IPC 912
Wet venting is permitted by IPC Section 912 (Wet Venting) when properly configured. The wet vent must be at least 2 inches and serve as both drain and vent for bathroom group fixtures. The dry vent portion must connect at or above the highest fixture drain, and the wet vent receives fixtures in a top-to-bottom arrangement. This bathroom group configuration is a common and compliant wet vent layout.
IPC 917
AAVs are permitted by the IPC when a conventional vent is not feasible, provided: the AAV is listed (ASSE 1051), installed at least 4 inches above the fixture drain, within the maximum developed length of the trap arm, accessible for service, and the building has at least one conventional vent stack open to atmosphere. This installation meets all requirements.
IPC Section 604.8
This passes code. IPC Section 604.8 requires that water pressure at any fixture not exceed 80 psi. The system design maintains maximum 75 psi at the lowest fixture in each zone, which is within the 80 psi limit. The lowest zone (floors 1-12) at 65 psi from city main pressure does not need a PRV since it already falls below 80 psi at all fixtures. The three upper zones each have PRV stations that reduce the booster pump output pressure to appropriate zone pressures. This is a well-designed high-rise plumbing system that properly addresses the 0.433 psi per foot of elevation head that makes pressure management essential in tall buildings.
IPC Table 709.1
Kitchen sinks require a minimum 1-1/2" drain. The 1-1/4" size is only permitted for lavatory (bathroom) sinks. An undersized kitchen drain will clog frequently from food waste.
IPC Table 710.1(1)
Per IPC Table 710.1(1), a 3-inch horizontal building drain at 1/8" per foot slope can handle up to 36 drainage fixture units (DFU) (42 DFU is the capacity at the steeper 1/4" per foot slope). With only 12 DFU on this line, it is well within the capacity of the 3-inch pipe. The critical factor is that no single branch carries more than its rated capacity, and no more than two water closets discharge into a 3-inch horizontal branch. This installation is compliant.
IPC Table 906.1
For a 1-1/4" trap arm, the maximum distance to the vent is 5 feet. Exceeding this distance risks siphoning the trap seal. The trap arm distance is measured from the trap weir to the vent connection.
CraftIQ explanations are original educational commentary written in trade language and verified against the cited standards. Always confirm requirements against the code edition adopted by your jurisdiction — this is training material, not a substitute for the code book or your AHJ.