ICC M1 cheat sheet

A permit is required before installing, altering, replacing, or repairing a mechanical system; ordinary repairs that do not change capacity or safety are exempt.

Approved construction documents and the permit must remain available on site, and field changes require revised approval before the work proceeds.

Concealed mechanical work such as ducts, piping, and vents must be inspected and approved before it is covered.

Materials and equipment must be listed and labeled by an approved agency and installed in accordance with the listing and manufacturer instructions.

The code official may issue a stop-work order for work performed without a permit or contrary to the code; work stops until the order is resolved.

Appeals of code official decisions are heard by the board of appeals, and the appeal must be filed within the time specified by the jurisdiction.

A permit becomes invalid if work does not commence within 180 days of issuance or is suspended or abandoned for 180 days, unless extended.

In code language, 'shall' is mandatory, 'may' is permissive, and 'approved' means accepted by the code official.

Approved: accepted by the code official as meeting the code, typically through listing, labeling, or other evidence of suitability.

Listed: equipment or materials included in a list published by an approved agency that maintains periodic inspection of production.

Labeled: equipment or materials bearing the label, symbol, or mark of an approved listing agency.

Occupiable space: an enclosed space intended for human occupancy, excluding closets, storage rooms, parking garages, and crawl spaces.

Plenum: a space used for air distribution that is part of an HVAC system; combustible materials and storage in plenums are restricted.

Combustion air: the air required by a fuel-burning appliance for combustion and draft, supplied from indoors, outdoors, or both.

Dwelling unit: a single housekeeping unit with permanent provisions for living, sleeping, eating, cooking, and sanitation.

Referenced standards are enforceable as part of the code for the specific subject matter and edition adopted by the jurisdiction.

Heating appliances in private garages must have ignition sources elevated at least 18 inches above the floor unless listed for a lower installation height.

Clearances to combustible materials must follow the listing, label, or code table and may be reduced only with approved protection.

Appliances located in closets or alcoves must have adequate combustion air, access for service, and protection from obstruction by doors or stored items.

Service access must allow inspection, repair, and replacement, including removal of the largest component of the appliance.

Natural ventilation requires operable openings to the outdoors with openable area not less than 4 percent of the floor area being ventilated.

Mechanical ventilation rates are determined from occupancy tables using occupant density and floor area, then supplied during occupied periods.

Direct-fired heating equipment must be installed according to its listing and the occupancy restrictions applicable to the space served.

Heating and ventilation equipment must be supported and fastened securely, and joints and connections must be tight and approved for the application.

The primary condensate drain must be at least 3/4 inch nominal size and slope at least 1/8 inch per foot toward an approved disposal point.

A secondary drain pan is required where condensate overflow could cause damage; the pan must be watertight, at least 1.5 inches deep, and drained.

Condensate traps must be installed per manufacturer instructions with sufficient depth to overcome fan pressure and prevent air from being drawn through the drain.

Condensate must discharge to an approved location and must not create a nuisance or discharge onto a public way or adjacent property.

Outdoor condensing units require manufacturer-specified clearances so discharge air is not recirculated and service access is maintained.

Air-conditioning equipment must be accessible for service and installed level or at the slope required by the manufacturer.

Refrigerant lines must be supported, protected from physical damage, and insulated where required to prevent condensation or energy loss.

Duct connections to air-conditioning equipment must be sealed and mechanically secured to prevent leakage.

Refrigerants are classified by toxicity and flammability: A1 is lower toxicity and no flame propagation; B1 is higher toxicity and no flame propagation.

A2, A3, B2, and B3 refrigerants have flammability characteristics and require additional safety measures.

A machinery room is required when refrigerant quantity exceeds the code threshold or when required for the occupancy and refrigerant group.

Machinery rooms require mechanical ventilation, refrigerant detection where required, and access and construction features specified by the code.

Refrigerant detectors must activate alarm or ventilation before concentrations reach hazardous levels.

Pressure-relief devices must discharge outdoors to a safe location away from windows, doors, and air intakes.

Refrigerant piping must be supported and protected from physical damage, and joints must be accessible where required for service.

Refrigerant quantity limits in occupied spaces are based on refrigerant group, occupancy classification, and whether the system is high-probability.

Ducts must be constructed and sealed in accordance with an approved duct construction standard such as SMACNA or an approved equivalent.

Duct joints, seams, and connections must be sealed to the required seal class to limit air leakage.

Return air cannot be taken from bathrooms, kitchens, garages, closets, mechanical rooms, or unconditioned attics.

Flexible air ducts must be installed fully extended, supported per the manufacturer, and with bends that do not restrict airflow.

Fire dampers are required where ducts penetrate fire-resistance-rated assemblies, and smoke dampers where required by the code.

Underground and under-floor plenums must be constructed and sealed to prevent entry of soil gas, moisture, and contaminants.

Duct insulation and vapor retarders must be installed to prevent condensation and must comply with the adopted energy code.

Horizontal ducts must be supported at intervals allowed by the duct construction standard, independent of duct joints and connections.

A chimney must extend at least 3 feet above the highest point where it passes through the roof and at least 2 feet above any building within 10 feet.

Type B gas vents must terminate at least 2 feet above the highest roof point within 10 feet and at least 5 feet above the appliance draft hood.

Category I appliances use vertical chimneys or vents designed for negative pressure; Category IV appliances require special positive-pressure venting.

Vent connectors must slope upward toward the chimney or vent, be as short and direct as practicable, and be supported.

A confined space is one with a volume less than 50 cubic feet per 1,000 Btu/h of total appliance input.

Combustion air openings must be permanent, unobstructed, and located one within 12 inches of the top and one within 12 inches of the bottom of the enclosure.

Indoor combustion air through two openings requires at least 1 square inch free area per 1,000 Btu/h input, with a minimum of 100 square inches per opening.

Outdoor combustion air through two openings requires at least 1 square inch free area per 4,000 Btu/h input; vertical ducts use 1 per 4,000 and horizontal ducts use 1 per 2,000.