Plain English:
510.1.2 Discharge pipe
Discharge piping must meet IMC duct requirements, including any required clearances for high-heat conditions.
Cyclone delivery pipe shall not discharge refuse directly into a boiler/furnace/Dutch oven/refuse burner/incinerator (or similar firebox).
510.1.4 Spark protection
Open-air exhaust terminals must have an approved noncombustible screen to prevent spark entry.
On Plans: Why it matters
Redlines usually come from "piping" shown without duct/clearance basis, cyclone discharge routed to a firebox, or terminals missing spark screens.
Code Path: Where to show it
M-001: "DISCHARGE PIPING SHALL COMPLY WITH IMC DUCT REQUIREMENTS. NO CYCLONE DISCHARGE TO FIREBOX."
Roof/Elevation: tag the outlet "APPROVED NONCOMBUSTIBLE SPARK SCREEN."
Check: Do
Treat discharge piping like industrial ductwork: support, clearance, and routing shown clearly.
Call out spark screen at every open-air terminal.
Review Risk: Don't
Don't route cyclone delivery piping to any appliance firebox.
Don't leave terminals unprotected where sparks can enter.
Field Tip:
Do a quick "FIREBOX + SCREEN" check on every outlet: confirm the discharge destination is not a firebox, and the terminal is tagged with a spark screen.
Masterbuild QA Lens
Solid-fuel appliance exhaust per 510.1.1-510.1.2 must route through a listed solid-fuel cooking exhaust system - not standard grease duct. Confirm the duct material, clearances, and termination comply with the listing for solid-fuel applications. The discharge pipe and spark arrestor requirements must be shown on M-501.
Drawing / Submittal Check
For 510.1.2 (hood and enclosure design) and 510.1.4 (air velocity): the drawings must show the design capture velocity at each source, the hood type (enclosing, receiving, or exterior), and the duct velocity for each segment. For high-velocity product-conveying systems, show the wear liner locations and the access for replacement. Include the design velocity in the duct schedule.
Common Review Risk
Duct velocity for product-conveying systems must be high enough to keep the material in suspension - if the velocity drops, the material settles in the duct and eventually plugs it. The most common design error is a duct system where the velocity is calculated at maximum flow and is insufficient at minimum flow. Calculate the minimum transport velocity at the lowest expected airflow condition.
When To Escalate
Escalate when the product-conveying system serves a process with variable material flow rates - where the minimum transport velocity at minimum flow cannot be maintained without a variable-speed fan or a bypass system. Variable-flow conveying systems require controls coordination that is beyond standard mechanical design.
Special Exhaust Coordination
For specialty exhaust, start with the contaminant and source. Then confirm capture method, duct material, routing, discharge, separation, controls, and whether another consultant or AHJ review is required.
Duct System Coordination
Sections 510.1.2 and 510.1.4 set discharge velocity, direction, and location for specialized exhaust systems. Confirm the duct termination detail shows required discharge height, separation from intakes, and velocity at the outlet.