IAPMO UMC MI flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

Mechanical permit requirement

A permit is required before installing, altering, or replacing regulated mechanical equipment. The permit must be obtained from the authority having jurisdiction and work must follow approved plans.

Concealment inspection

Mechanical work cannot be covered or concealed until it has been inspected and approved. The contractor requests inspection before drywall, insulation, or other coverings are installed over the work.

Certificate of occupancy

Issued after final inspection confirms the mechanical installation complies with the approved plans and code. It authorizes occupancy or use of the completed building or space.

Stop-work order

An enforcement action by the AHJ halting work that is unsafe or noncompliant. Work may not resume until the cited condition is corrected and the order is lifted.

Board of appeals

The body established by local ordinance to hear appeals of AHJ decisions and interpretations. Appeals must be filed within the time and manner the jurisdiction specifies.

Approved plans on site

Approved drawings and the permit must be kept available at the job site for the inspector. Deviations from approved plans require a revised permit before proceeding.

AHJ authority

The authority having jurisdiction enforces the mechanical code, reviews plans, conducts inspections, and may revoke permits or order corrections for code violations.

Combustion air requirement

Appliances must receive adequate air for combustion, dilution, and ventilation. The code permits prescriptive opening methods or engineered designs that demonstrate sufficient air supply.

Plenum installation listing

Equipment and materials installed in air plenums must be listed for that use and meet limits on combustibility and smoke developed, reducing fire and smoke spread risk.

Garage equipment protection

Mechanical equipment in garages must be protected from vehicle damage and, where required, elevated so ignition sources sit above the floor to reduce vapor ignition.

Appliance access opening

Appliances in attics, crawl spaces, or closets need a service access opening sized to the equipment. Access must not pass through another tenant's space.

Refrigerant safety group

Refrigerants are classified by toxicity and flammability, such as A1, A2L, A3, and B1. Higher-risk groups face stricter charge limits, ventilation, and occupancy restrictions.

Condensate drain trap

Condensate drains require a trap where specified, must slope to a disposal point, and must be protected from freezing. Secondary drain or pan protection prevents overflow damage.

Duct pressure class

Ducts are classified by static pressure and velocity into pressure classes. Construction, sealing, and leakage class must match the class required for the system.

Equipment sizing load calculation

Sensible and latent loads are calculated by an accepted method to size equipment. Oversizing causes short cycling, poor dehumidification, and comfort problems.

External static pressure limit

Total external static pressure equals duct friction loss plus component pressure drops. It must not exceed the air handler's rated capability or airflow will fall short of design.

Refrigerant line sizing

Line size depends on capacity, equivalent length, and oil return. Suction lines must keep velocity high enough for oil return while liquid lines limit pressure drop.

Category IV venting

Condensing appliances are Category IV and require listed plastic venting installed with slope back to the appliance so condensate drains properly and does not pool.

Gas piping sizing methods

Gas piping is sized using the longest length or branch length method with the code tables, accounting for gas specific gravity and allowable pressure drop.

Flexible duct installation

Flexible duct runs should be short and straight. Compression and sharp bends reduce delivered airflow and effective capacity and should be avoided.

Outdoor unit clearance

Outdoor units need clearances for airflow and service per the listing. Recirculating discharge air reduces capacity and can trip high-pressure controls.

Return air restrictions

Return air cannot be drawn from bathrooms, kitchens, or garages. These spaces require dedicated exhaust, and return paths must have adequate free area.

Refrigerant pressure test

Refrigerant piping is pressure tested with dry nitrogen or as the code allows before evacuation. The system is then evacuated to a specified micron level and held.

Gas piping test

Gas piping is tested with air or inert gas at the code-specified pressure for the required duration. The test medium and gauge must be visible to the inspector.

Duct leakage testing

Where the code requires it, duct leakage is measured and must not exceed the leakage class for the duct's pressure class and seal level.

Combustion analysis

Combustion testing measures steady-state efficiency, flue and ambient carbon monoxide, and draft. Elevated CO indicates incomplete combustion or a venting problem.

Superheat and subcooling

High superheat with low subcooling suggests undercharge. High subcooling with high head pressure suggests overcharge or restricted airflow. These measurements verify charge.

Airflow verification

Airflow is measured with a duct traverse or flow hood and compared to design. Dampers or fan speed are adjusted to balance supply and return.

Plan review focus

Reviewers check equipment listings, clearances, combustion air, venting, duct class, and refrigerant safety group against code provisions before issuing a permit.

Notice of violation

A written enforcement notice identifies the code section, the specific defect, the required correction, and a reinspection date for the noncompliant installation.

Unsafe condition order

Blocked combustion air, disconnected vents, or refrigerant leaks into occupied space may be ordered corrected immediately, with equipment shut off until repaired.

Inspection documentation

Inspectors record findings with photographs, measurements, and test results. This record supports enforcement actions, reinspections, and any subsequent appeal.