Rehabilitation Subcode: Appendix III
Mechanical

Summary of Mechanical Subcode Requirements

Repair Section 6.4
In the context of mechanical work, repair essentially includes the replacement of equipment parts; repair of hydronic, gas, oil piping; or replacement of baseboard radiation with like. Repair as defined in the rehabilitation subcode has nothing to do with when a permit is required, rather it describes a level of work where minimal code compliance is required. An important feature of repair work is that it allows the use of outdated materials and methods in order to maintain existing mechanical equipment and systems. No specific mechanical requirements are listed.

Repairs must not increase loads on mechanical systems beyond code allowances.

Renovation Sections 6.5(c) and (g) and 6.8(e)
Renovation differs from repair in that the applicant has chosen to update a building feature. Renovation is not a "like with like"substitution, it is a substitution of one material with another or one type of appliance with another. Replacement of furnaces or equipment is a renovation. When renovation work is performed you must comply with materials and methods. Materials and methods are the "how to" sections of the code. They are not the "when to" sections of the code. In other words, they should not expand the scope of work beyond what the applicant has chosen to perform.

Example: If an applicant has chosen to replace his furnace/boiler, Materials and Methods requires that the furnace be listed and labeled, and installed in accordance with the manufacturers installation instructions. Materials and methods does not require that: Service clearances be maintained, convenience outlets be provided, lighting be provided, gas piping be resized (as long as the Btu input of the new appliance is the same as the existing, and the length of the piping system is not increased), the suppression be updated or the boiler or furnace rooms meet rating requirements.

Renovations must comply with:

Materials and Methods listed below and must not increase loads on mechanical systems beyond code allowances.

Mechanical Materials and Methods Sections 5:23-6.8(e)
The following sections of the mechanical subcode (NJAC 5:23-3.20) shall constitute the mechanical materials and methods requirements for this subchapter:

1. All of Chapter 3, entitled "Air Distribution Systems," except sections M-303.0, M-306.3, M-313.2 and M-314.0.
   
   1. Section M-303.0 shall apply to newly-constructed plenums. Modifications to existing plenums, such as installation of new building, electrical or plumbing materials inside the plenum, increasing air flow rate within the plenum, etc. shall not require the plenum to comply with the construction requirements for new plenums. However, newly-installed materials with the plenum shall be consistent with material requirements of M-303.0.
   
   
2. All of Chapter 4, entitled "Mechanical Equipment" except sections M-405.2, M-405.6, M-408.1, M-409.2, and M-409.3
   
3. All of Chapter 5, entitled "Kitchen Exhaust Equipment" except section M-508.1
   
   1. Section M-505.1 for hood suppression shall apply to newly-installed kitchen hoods. Modifications to existing hoods shall comply with the basic requirements of this subcode.
      
      
4. All of Chapter 6 entitled "Boilers and Water Heaters"
   
5. All of Chapter 7 entitled "Hydronic piping"
   
6. All of chapter 8, entitled "Gas Piping Systems" except section M-805.0.
   
   1. Section M-805.0 sizing shall apply when the work being performed increases the load of the system such that the existing pipe does not meet the size required by code. Existing systems that are modified shall not require resizing as long as the load on the system is not increased and the system length is not increased even of the altered system does not meet code minimums.
   
   
7. All of Chapter 9 entitled "Flammable and Combustible Liquid Storage and Piping Systems"
   
8. All of Chapter 10 entitled "Combustion Air"
   
9. All of Chapter 11 entitled "Clearance Reduction"
   
10. All of Chapter 12 entitled "Chimneys and Vents"
    
11. All of Chapter 13 entitled "Mechanical Refrigeration"
    
12. All of Chapter 14 entitled "Fireplaces, Solid Fuel-Burning and Gas Accessory Appliances"
    
13. All of Chapter 15 entitled :Incinerators and Crematories:
    
14. All of Chapter 16, entitled "Ventilation Air" except sections M-1603.0, M-1604.0 and M-1605.0
    
15. All of Chapter 18 entitled, "Solar Heating and Cooling Systems"
    
16. Section M-2001.2 of Chapter 20 entitled "Boilers and Pressure Vessels, Maintenance and Inspection."

Alterations Sections 6.6(c) and (g) and 6.8(e)
Installation of additional equipment is an alteration project. When equipment is added to an existing fuel supply system, the system may need to be resized if the additional load takes the system out of compliance with code minimums. Extending ductwork would also be an alteration.

Alterations must:

Comply with Materials and Methods;
Not reduce compliance with basic. (e.g. cannot create new space in a building that is not provided with ventilation);
Not increase loads on mechanical systems beyond code allowances.

Reconstruction Sections 6.7(c) and (h), 6.8(e) and 6.12(l), 6.13(m), 6.14(m), 6.15(l), 6.16(l), 6.17(l), 6.18(l), 6.19(l), 6.20(m), 6.21(n), 6.22(o), 6.23(n), 6.24(l), 6.25(p), 6.26(o), 6.28(l).
Reconstruction would generally be a tenant fit up or a gut rehabilitation project. Reconstruction is a repair, renovation, alteration (or combination) where the work is so extensive that the space being worked on cannot be occupied while the work is in progress. A project is a reconstruction when the following conditions are met:

1. The area where the work is being performed constitutes an entire use, an entire tenancy, or a room or space housing a major activity for which the building or tenancy is intended, including but not limited to an office area, auditorium, assembly space, dining room, bar or lounge, warehouse, factory, dwelling, care, confinement, retail or educational spaces. This does not include kitchens, bathrooms, storage rooms, or other spaces that support the primary function space of the building.
   
2. The work must be so extensive that the work area cannot be occupied and a new certificate of occupancy is required for the space.
   Exception: Work limited to carpeting, or ceiling tile replacement is not reconstruction.

There are basic mechanical requirements for minimum ventilation. These requirements are intended to require an upgrade of the mechanical system when the existing system is so substandard that it does not provide a minimally acceptable level of ventilation.

Reconstructions must comply with:

Materials and Methods.
Not increase loads on mechanical systems beyond code allowances.

The following basic requirements within the work area (but these are not applicable to Use Groups R-3/R-4):
All spaces intended for occupancy shall be provided with either mechanical or natural ventilation.

1. Spaces intended to be naturally ventilated shall be provided with openable doors, windows, louvers or other openings to the outdoors. The minimum openable area to the outdoors shall be 4 percent of the floor area being ventilated. Where rooms without openings to the outdoors are ventilated through an adjoining room, the unobstructed opening to the adjoining room shall be at least 8 percent of the floor area of the interior room or space, but not less than 25 square feet. The ventilation openings to the outdoors shall be based on the total floor area being ventilated.
   
2. Mechanically ventilated spaces shall comply with the following:
   
   1. Newly installed HVAC systems shall comply with ASHRAE 62-89.
      
   2. Existing systems that are altered or extended shall not reduce the amount of outside the existing rate per person or the rate included in ASHRAE 62-89 whichever is lower. As a minimum, mechanically ventilated spaces shall be provided with 5 CFM per person of outdoor air and 15 CFM of ventilation air per person unless the indoor air quality procedure of ASHRAE 62-89 is followed and results in a lesser amount.
   
   
3. All newly-introduced devices, equipment or operations that produce airborne particulates, odors, fumes, sprays, vapors, smoke or gases in such quantities to be irritating or injurious to health shall be provided with local exhaust.

There are no supplemental mechanical requirements.

Change of Use Section 6.31(n)
Applies to change of use group as defined in the building subcode and applies to a change that would trigger a use specific requirement in any other subcode.

Change of use must comply with:
Upgrade mechanical ventilation system if the new use would require more ventilation air based on the requirements of the new code. If the new use is a use that requires less ventilation air based on the new code no upgrade is required.
Work associated with the change of use must comply with the repair, renovation, alteration or reconstruction work portion of the code as appropriate.

Additions Section 6.32
Any addition to a building or structure shall comply with the requirements of the Uniform Construction Code applicable to new construction. Any repair, renovation, alteration, or reconstruction work undertaken within an existing building in connection with an addition shall comply with the requirements of the rehabilitation subcode. No addition shall create or extend any non-conformity in the existing building to which the addition is constructed with regard to the capacity of mechanical systems.

Historic Buildings Section 6.33
Material and Methods - original or replica material and original methods of construction may be used, subject to the provisions of this section.
Exception: Components of building systems hidden from public view, including but not limited to electrical equipment and wiring, plumbing equipment and piping and heating equipment, shall comply with Section 6.8.

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