CODES

Some detailed code book information is shown below as a quick reference for our customers. Please contact our office if you have specific questions about current codes and how they may apply to your installation.

Detailed Code Reference

General Codes Requirements
Permit: MC 106.1
When required, an owner, authorized agent or contractor who desires to erect, install, enlarge, alter, repair, remove, convert or replace a mechanical system, the installation of which is regulated by the mechanical code, or to cause such work to be done, shall first make application to the code official and obtain the required permit for the work.


MC 106.2
Exemption from the permit requirements of this code shall not be deemed to grant authorization for work to be one in violation of the provisions of this code or other laws or ordinances of this jurisdiction.


Energy Utilization: MC 301.2
Heating, ventilation and air-conditioning systems of all structures shall be designed and installed for efficient utilization of energy in accordance with the International Energy Conservation Code.


Installation: MC 304.1
Heating and cooling equipment and appliances shall be installed in accordance with the manufacturer’s installation instructions and the requirements of this code.


Conflicts: MC 304.2
Where conflicts between this code and the conditions of listing or manufacturer’s installation instructions occur, the provisions of the code shall apply.
Exception: Where a code provision is less restrictive than the conditions of the listing of the equipment or appliance or manufacturer’s installation instructions, the conditions of the listing and manufacturer’s installation instructions shall apply.


Sizing: RC M1401.3
Heating and cooling equipment shall be sized in accordance with ACCA Manual S based on building loads calculated in accordance with ACCA Manual J or other approved heating and cooling calculation methodologies.


Duct Sizing: MC 603.2
Ducts installed within a dwelling unit shall be sized in accordance with ACCA Manual D or other approved methods.


Programmable thermostat: ECC 403.1.1
Where the primary heating system is a forced-air furnace, at least one thermostat per dwelling unit shall be capable of controlling the heating and cooling system on a daily schedule to maintain different temperature set points at different times of the day. This thermostat shall include the capability to set back or temporarily operate the system to maintain zone temperatures down to 55ºF (13ºC) or up to 85ºF (29ºC).

Programmable thermostat: ECC 403.1.1
The thermostat shall initially be programmed with a heating temperature set point no higher than 70ºF (21ºC) and a cooling temperature set point no lower than 78ºF (26ºC).


(Stairway and Decking) Access and service space: MC 306.1
Appliances shall be accessible for inspection, service, repair and replacement without removing permanent construction, other appliances, or any other piping or ducts not connected to the appliance being inspected, serviced, repaired or replaced. A level working space at least 30 inches deep and 30 inches wide (762 mm by 762mm) shall be provided in front of the controls side to service an appliance. Attics containing appliances shall be provided with an opening and unobstructed passageway large enough to allow removal of the largest appliance. The passageway shall not be less than 30 inches high and 22 inches wide and not more than 20 feet in length along the centerline of the passageway from the opening to the appliance. The passageway shall have continuous solid flooring not less than 24 inches wide. A level working space at least 30 inches deep and 30 inches wide shall be provided in front of the control side to service an appliance. The clear access opening dimensions shall be a minimum of 20 inches by 30 inches, and large enough to allow removal of the largest appliance.
*(Amended by most local municipalities)
As a minimum, access to the attic space shall be provided by one of the following:
1. A permanent stair
2. A pull down stair
3. An access door from an upper floor level
4. An access panel in lieu items 1, 2 or 3 with prior approval of the code official due to structural conditions.
(OUR POLICY: IS ONLY TO WORK ON A STRUCTURALLY SOUND PULL DOWN STAIR FOR THE REMOVAL AND INSTALLATION OF EQUIPMENT. WE ARE NOT RESPONSIBLE FOR ANY DAMAGE TO THE STAIRS, FLOORS, WALLS, OR ANY OBJECTS BROKEN FROM THE FAILURE OF THE PULL DOWN STAIR SYSTEM.)
 

(Attic Light) Electrical requirements: MC 306.3.1
A luminaire controlled by a switch located at the required passageway opening and a receptacle outlet shall be provided at the appliance location in accordance with NFPA 70.


(Mastic sealing of unit) Joints, seams and connectors: MC 603.9
Joints of duct systems shall be made substantially airtight by means of tapes, mastics, liquid sealants, gaskets or other approved closure systems. Closure systems used with rigid fibrous glass ducts shall comply with UL181A and shall be marked 181A-P for pressure-sensitive tape, 181A-M for mastic or 181A-H for heat sensitive tape.


(Sealing of unit) Joints, seams and connectors: MC 603.9
Closure systems used with flexible air ducts and flexible air connectors shall comply with UL 181B and shall be marked 181B-FX for pressure-sensitive tape or 181B-M for mastic. Duct connections to flanges of air distribution system equipment or sheet metal fittings shall be mechanically fastened. Mechanical fasteners for use with flexible nonmetallic air ducts shall comply with UL 181B and shall be marked 181B-C. Crimp joints for round metal ducts shall have a contact lap of at least 11/2 inches (38mm) and shall be mechanically fastened by means of at least three sheet-metal screws or rivets equally spaced around the joint. Closure systems used to seal metal ductwork shall be installed in accordance with the manufacturer’s installation instructions.


(Balancing dampers) Air system balancing: MC 603.17
Volume dampers or other means of supply air adjustment shall be provided in the branch ducts or at each individual duct register, grill or diffuser. Each volume damper or other means of supply air adjustment used in balancing shall be provided with access.


(Insulation Upgrade) Insulation: ECC 403.2.1
Supply ducts in attics shall be insulated to a minimum of R-8. All other ducts shall be insulated to minimum of R-6.

Gas Furnace


(Flue Piping) Vent connectors for Category 1 appliances: FGC 503.10
Vent connectors for category 1 appliances shall comply with Sections 503.10.1 through 503.10.15.


Residential-type appliance connectors: FGC 503.10.2.2
Where the vent connector used for an appliance having a draft hood or Category 1 appliance is located in or passes through attics, crawl spaces or other unconditioned spaces, that portion of the vent shall be listed Type B, Type L or listed vent material having equivalent insulation properties.


Clearance: FGC 503.10.5
Minimum clearances from vent connectors to combustible material shall be in accordance with Table 503.10.5 & 308.2 (Minimum of 1”)


Sizing: FGC 504 – Section 504 relates to the sizing, pitch and number of fittings for Category 1 appliance venting systems.


(Gas Piping) Sediment trap: FGC 408.4
Where a sediment trap is not incorporated as part of the appliance, a sediment trap shall be installed downstream of the appliance shutoff valve as close to the inlet of the appliance as practical.


Connecting appliances: FGC 411.1.3.4
Prohibited locations and penetrations:
1. Rigid steel pipe shall extend through openings in appliance housings.
2. Corrugated stainless steel tubing (CSST) where installed in accordance with the manufacturer’s instructions.
3. Semirigid metallic tubing and metallic fittings. Lengths shall not exceed 6 feet (1829 mm) and shall be located entirely in the same room as the appliance. Semirigid metallic tubing shall not enter a motor-operated appliance through an unprotected knockout opening.
4. Listed and labeled appliance connectors in compliance with ANSI Z21.24 and installed in accordance with the manufacturer’s instructions and located entirely in the same room as the appliance.
5. Listed and labeled quick-disconnect devices used in conjunction with listed and labeled appliance connectors.
6. Listed and labeled convenience outlets used in conjunction with listed and labeled appliance connectors.
7. Listed and labeled outdoor appliance connectors in compliance with ANSI Z21.75/CSA 6.27 and installed in accordance with the manufacturer’s instructions.


Gas shutoff valve: FGC: 411.1.3.4
A shutoff valve not less than the nominal size of the connector shall be installed ahead of the connector.


ANSI/ASME B16.44-2002
Manually Operated metallic Gas Shutoff Valves for Use in House Piping Systems

This standard applies to new valve construction and covers quarter turn manually operated valves in sizes NPS-4 and tubing sizes -1 O.D. These valves are intended for indoor installation as gas shutoff valves when installed in above ground fuel gas piping downstream of the gas meter outlet and upstream of the inlet connection to a gas appliance. The valves covered by this standard are intended for service at temperatures between 32ºF (0ºC) and 125ºF (52ºC) at pressure ratings not exceed 5 psi (0.34 bar). When so designated by the manufacturer, these valves may be installed for service outdoors and/or at temperatures below 32ºF (0ºC) and/pr above 125ºF (52ºC).

* Red handle valves designed for indoor temperature range 32-125. Yellow handle valves designed for operation outside temperature range 32-125.


Hanging/Support modifications: MC 304.1 & 304.2 (See general codes)
Suspended Furnace Support (per mfg.)
The furnace may be supported under each end with threaded rod, angle iron or 1½” metal strap. Secure angle iron to bottom of furnace. Heavy—gauge sheet metal straps may be used to suspend the furnace from each bottom corner. To prevent screws from pulling out, use 2 #8 x ¾ in. (19mm) screws in the bottom of the furnace casing for each strap.


Electrical disconnect (light switch): RC E4101.5
Each appliance shall be provided with a means to disconnect all ungrounded supply conductors. For fixed electric space-heating equipment, means shall be provided to disconnect the heater and any motor controller(s) and supplementary overcurrent-protective devices. Switches and circuit breakers used as a disconnecting means shall be of the indicating type. (See Table E4101.5.)
DESCRIPTION ALLOWED DISCONNECTING MEANS
Permanently connected appliance rated at not over 300 volt-amperes or 1/8 horsepower. Branch circuit breaker or switch located within sight of appliance or such devices in any location that are capable of being locked in the open position. The provision for locking or adding a lock to the disconnecting means and shall remain in place with or without the lock installed.


Combustion air screen: FGC 618.6
Required outdoor air inlets for residential portions of a building shall be covered with a screen having ¼ inch openings.

Increase Combustion air: FGC 304.6, 304.6.1 & 304.6.2
Outdoor combustion air shall be provided through openings to the outdoors. One permanent opening or two permanent openings, one opening within 12 inches of the top of the enclosure communicating through a duct to the outdoors or space that freely communicates to the outdoors, or two openings within 12 inches from the top and one within 12 inches from the bottom through a duct to the outdoors or space that freely communicates to the outdoors of the enclosure. One opening shall have 1 square inch of free air space per 3.000 BTU/H or two openings shall have 1 square inch of free air space per 4,000 BTU/H if vertical & 2,000 BTU/H if horizontal.


Carbon Monoxide Alarms: RC R 315.2
Where required in existing dwellings. Where work requiring a permit occurs in existing dwellings that have attached garages or in existing dwellings within which fuel-fired appliances exist, carbon monoxide alarms shall be provided in accordance with Section R315.1.

Evaporator Coil/ Air Handler
Condensate float switch: MC 307.2.3 part 4
A water level detection device conforming to UL 508 shall be provided that will shut off the equipment served in the event that the primary drain is blocked. The device shall be installed in the primary drain line, the overflow drain line, or in the equipment supplied drain pan, located at a point higher than the primary drain line connection and below the overflow rim of such pan.


Add/Replace emergency drain pan: MC 307.2.3 part 1
An auxiliary drain pan with a separate drain shall be provided under the coils on which condensation will occur. The auxiliary pan drain shall discharge to a conspicuous point of minimum depth of 1 ½ inches, shall not be less than 3 inches larger than the unit or coil dimensions in width and length and shall be constructed of corrosion resistant material.


Drain modification/trap: MC 307.2.2
All components shall be selected for the pressure and temperature rating of the installation. Joints and connections shall be made in accordance with the applicable provisions of Chapter 7 of the International Plumbing Code.


MC 307.2.4 – Condensate drains shall be trapped as required by the equipment or appliance manufacturer. (Typical manufacturer requires a 4 to 5 inch p-trap)


MC 705.14.2 – Joint surfaces shall be clean and free from moisture. Purple primer shall be applied. Solvent cement not purple in color shall be applied to all joint surfaces.


MC 305.4 – Piping shall be supported at distances not exceeding the spacing specified in Table 305.4, (PVC pipe maximum horizontal support spacing 4ft.)


MC 1206.11 – Condensation. Provisions shall be made to prevent the formation of condensation on the exterior of piping. (Insulate piping with insulation)

Electrical Disconnect & Whip for air handler:
**See electrical disconnect of gas furnace
Hanging/Support modifications:
**See hanging/support of gas furnace.

Compressor/Heat Pump/Air Conditioner


Low voltage conduit: NEC 708.14
Wiring of HVAC, fire alarm, security, emergency communications, and signaling systems. All conductors or cables shall be installed using any of the metal wiring methods permitted by 708.10(C)(1) and in addition shall comply with 708.14(8) as applicable.
*708.10(C)(1) Protection against physical damage. (708.10(C)(1)(3)(C)


Electrical disconnect: RC E4101.5
Each appliance shall be provided with a means to disconnect all ungrounded supply conductors. For fixed electric space-heating equipment, means shall be provided to disconnect the heater and any motor controller(s) and supplementary overcurrent-protective devices. Switches and circuit breakers used as a disconnecting means shall be of the indicating type. (See Table E4101.5.)
DESCRIPTION ALLOWED DISCONNECTING MEANS
Permanently connected appliance rated at not over 300 volt-amperes or 1/8 horsepower. Branch circuit breaker or switch located within sight of appliance or such devices in any location that are capable of being locked in the open position. The provision for locking or adding a lock to the disconnecting means shall be installed on or at the switch or circuit breaker used as the disconnecting means and shall remain in place with or without the lock installed.


Locking Caps: MC 1411.6
Locking access port caps. Refrigerant circuit access ports located outdoors shall be fitted with locking-type tamper-resistant caps.  Section 1102.3 Expanded to apply to existing systems when service to such system involves adding or removing refrigerant.


Slab above grade: MC 304.10
Equipment and appliances installed at grade level shall be supported on a level concrete slab or other approved material extending not less than 3 inches above adjoining grade. Unit must be level to within ±2_ (±3/8 in./ft.) per compressor manufacturer specifications.


Clearance Requirements (per manufacturer): When installing air conditioner or heat pump, allow sufficient space for airflow clearance, wiring, refrigerant piping, and service. Allow 24 inches clearance to service end of unit and 48 inches above unit. For proper airflow, a 6 inch clearance on 1 side of unit and 12 inches on all remaining sides must be maintained. Maintain a distance of 24 inches between unit or 18 inches if no overhang within 12 feet. Position so water, snow, or ice from roof or eaves cannot fall directly on unit. Note: 18” clearance option described above is approved for outdoor units with wire grill coil guard only. Units with louver panels requires 24” between units.

Insulation of refrigerant piping: RC M1411.5
Piping and fittings for refrigerant vapor (suction) lines shall be insulated with insulation having a thermal resistivity of at least R-4.


Auxiliary heat lock-out: ECC 403.1.2 & RC N1103.1.2
Heat pumps having supplementary electric-resistance heat shall have controls that, except during defrost, prevent supplemental heat operation when the heat pump compressor can meet the heating load.

Equipment and refrigerant disposal:
EPA Clean Air Act: Section 608 prohibits individuals from intentionally venting ODS refrigerants (including CFCs and HCFCs) and their substitutes (such as HFCs), while maintaining, servicing, repairing, or disposing of air conditioning or refrigeration equipment. Technicians must evacuate air-conditioning and refrigeration equipment to established vacuum levels during servicing and disposal. Service technicians, owners, and operators of large refrigeration and air-conditioning equipment, refrigerant wholesalers, and EPA-certified refrigerant reclaimers are required to maintain records documenting dates, refrigerant charge amounts, and related information for equipment servicing and disposal.

Drain Line Valves: MC  307.2.5

Condensate drain lines shall be configured to permit the clearing of blockages and perform maintenance without requiring the drain line to be cut.

306.5 IMC Equipment and appliances on roofs or elevated structures.

Where equipment requiring access or appliances are located on an elevated structure or the roof of a building such that personnel will have to climb higher than 16 feet (4877mm) above grade to access such equipment or appliances, an interior or exterior means of access shall be provided. Such access shall not require climbing over obstructions greater than 30 inches (762mm) in height or walking on roofs having a slope greater than 4 units vertical in 12 units horizontal (33-percent slope). Such access shall not require the use of portable ladders. Where access involves climbing over parapet walls, the height shall be measured to the top of of the parapet wall.

Air​​​

Conditioning
Ventilation
Heating

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