The Mechanical and Plumbing design guidelines apply to all design including formal and informal construction performed by outside contractors and in-house shops.
During design, the designer shall be familiar with the manufacturer’s installation instructions for all specified equipment and components. During design, the designer shall incorporate ‘recommended’ manufacturer’s installation instructions into the bid documents in addition to manufacturer’s “required” installation instructions. At the time of inspection, the designer shall verify that installations fully comply.

The manufacturer’s installation instructions shall be available on the job site at the time of inspection and startup as required by NCMC 304.1.

Submittals shall include a copy of all relevant specifications. For each specification section and subsection the submittal shall indicate either “complies” or “deviates” and with explanation. The specification shall precede the product information.

Submittals shall contain the manufacturer’s installation instructions.

General

Clearances around equipment including air terminals, reheat coils, and air valves shall be sufficient to allow inspection, service, repair or replacement without the need to remove elements of permanent construction such as conduits, pipe, ducts, cable trays, etc. All trades must coordinate and protect the service area around equipment. It is emphasized that equipment above ceilings must have access for replacement without the need to remove unrelated systems. Designers shall indicate, on the plans, minimum clear maintenance access for all major equipment including air handlers, terminal units, air valves, fan coils, heat exchangers, boilers, chillers, air compressors, pumps, motors, fans, control valves (greater than 3″), etc. This should be indicated with a light, dashed line, cross-hatch, or within detail drawings.

Suspended ceiling clearances

Provide 2″ minimum clearance (or two times the ceiling tile thickness) between the suspended ceiling grid and the overhead building systems and structure to allow for ceiling tile removal. This requirement applies to all construction trades. The MEP designer is responsible for coordinating this requirement with the architect.

Height requirements

  1. Equipment requiring frequent maintenance, such as pumps, motors, control valves, humidifiers, and control valves should be installed below 13′ elevation.
  2. For equipment mounted over 13′ elevation, provide fall-protection tie-offs and platforms as required by OSHA.
  3. For equipment mounted over 15′, assure that an extension ladder may be used and provide structural ladder hold-offs as needed and / or an access platform. The NC Mechanical Code requires a permanent means of access for equipment over 16′.
  4. For equipment over 20′, provide an access platform. Provide stairs or ship ladder with a cage when possible (to avoid uncaged ship ladders). Avoid alternating stair treads.

Lifting means

For heavy equipment that may require occasional replacement and when the equipment weight is in excess of 150 pounds with limited access or when over 8 feet in elevation and in excess of 50 lbs., provide means for equipment replacement such as attachment points for chainhoists, mono-rails, jib-cranes, etc. Provide permanent lifting chains when attachment points are over 13′ elevation. Typical equipment that applies includes large pumps, motors, control valves, tube bundles, etc. Equipment between 150 and 500 pounds and 2 feet to 8 feet elevation may be removed by engine hoist if clear working space is provided.

Access doors

All serviceable equipment (smoke dampers, fire dampers, control dampers, duct smoke detectors, fans, valves, coils, terminal units, pumps, filters, isolation valves, clean-outs, junctions, etc.) installed behind an inaccessible finished surface requires the installation of suitable access doors. Ensure that access is not blocked by conduit, wire trays, ductwork, etc.

Refer to “HVAC Air Distribution” for additional requirements for duct access doors.

Minimum access requirements

  1. Air Handlers: 36 inches minimum access for fan compartments with motors 10 hp and larger. Provide coil pull access for the length of the coil plus 6 inches and the width of the coil plus 30 inches on both sides. Provide a means and a pathway for replacing the entire air handler without major demolition.
  2. Boilers: Provide 24 inches on all sides except the burner, which should have 36 inches minimum.
  3. Control valves: For valves 3 inches and larger, provide access above the valve of the assembly height plus 12 inches.
  4. Heat Exchangers: Provide tube pull plus 12″ for shell and tube type exchangers.

General

  1. All new and reused equipment installed under the project scope of work shall be cleaned and in new condition (inside and outside) at the time of acceptance. Reused equipment shall only be used if specified and approved and shall be refurbished to “like new” condition.
  2. Cleaning solutions or anything other than water shall not be discharged to the storm sewer system.
  3. Spare parts shall be turned over to the owner via the UNC construction manager.
  4. The contractor shall be responsible for maintenance until training is complete and the O&M manual(s) are delivered and approved by Building Services.
  5. Warranty: Contractors standard 1-year warranty starts at the beneficial occupancy of the area accepted or additional warranties apply to their terms.)

Requirements for operating HVAC equipment during construction

  1. Building must be fully enclosed, including installation of all doors, windows, etc.
  2. Set air handler to use 100% OA if construction is still generating dust and when conditions will not allow the coil to freeze.
  3. If return air is to be used then all exhaust and return ducts/grilles shall be covered with temporary filter media, minimum MERV 8, to prevent dust infiltration into the ducting.
  4. All chilled water piping shall be insulated.
  5. Pump and fans shafts shall be aligned prior to operation. Laser alignment shall be provided for pumps, and reports shall be furnished prior to operation.
  6. Supply and outside air connections of ductwork to AHUs shall be complete.
  7. All manual dampers, fire dampers and combination fire/smoke dampers shall be open.
  8. All main supply ductwork shall be insulated.
  9. All safety circuits and basic control functions shall be active and fully functional. If the equipment may operate without a fully functional BAS, then means to prevent damage to ducting due to closed dampers and means to prevent damage to freezing coils shall be provided. Blow-out doors may be used to protect ducting. Until TAB activities commence, fans and pumps shall operate at no more than 70% of estimated design capacity.
  10. Conditioning (cooling & dehumidifying) of the building shall remain once started.
  11. Final approval of UNC is required prior to starting AHUs for temporary operation.
  12. Cover outside air intakes with 1″ roll filter media.
  13. The contractor shall perform all required preventative maintenance on mechanical equipment operated during construction and provide documentation in the operation and maintenance manuals of preventative maintenance activities completed during this period.
  14. At the end of the construction period and prior to occupancy, clean the inside of AHUs and if more than 50% loaded, then install new pre and final filters.
  15. AHU UV lights shall be operational and all specified filters installed during all AHU operation.

Cleaning and treating the domestic water system

  1. For all fixtures with aerators, remove the aerator before flushing. After flushing, rinse the aerators and reinstall.
  2. Operate booster pumps to achieve maximum pipe velocity and flushing effectiveness.
  3. With all aerators removed, let the water run through the fixtures for 10 minutes at the highest flow rate.
  4. Forming a protective layer on the brass in the system: Turn on the cold water for all faucets in the building, such that some water flows out for 3 days at low flow. Any flow rate from 2 drips per second to a small “trickle” from each fixture is adequate. Very high flow rates should be avoided because they waste water and, if taken to an extreme, might actually prevent formation of a protective layer.
  5. Notify the EHS Occupational and Environmental Hygiene Manager when building flushing begins and are complete. Provide the building and the site contact information.
  6. Overflow Pipes: Extend all equipment overflow or blow-down lines to a floor sink or floor drain connected to the sanitary sewer system.
  7. The designer shall specify appropriate cleaning and disinfecting procedures for domestic water piping systems, compliant with AWWA and OWASA (below grade domestic water piping only).

Cleaning and treating the hydronic piping

  1. Specify flushing and cleaning for piping systems before they are put into service. Do not utilize building pumps for circulating cleaning fluid to maintain design water velocities for the duration of the test. Flush system at 4 fps minimum velocity.
  2. For new pipe systems, specify a closed-loop cleaning procedure such as Chem-Aqua TB 3-001.
  3. Passivate new systems for a minimum of 5 days.
  4. When adding to existing loops, fund a work order for HVAC Services to treat the loop.
  5. Bypass all coils during flush and cleaning process. Provide startup pump strainers or temporary pumps during flush and cleaning process.

General

Should the University or the Designer have any reasonable doubt as to the proper functioning of any equipment installed under this Contract, at any time during the guarantee period; the University and/or Designer has the right to perform any test deemed practical to determine whether such equipment is functioning properly and performing at specified capacity.

Specify factory certified start-up and inspection for vacuum pumps, air compressors, pumps, AHUs, fans, boilers, VFDs and water heaters.

Provide a complete list of all required factory certified start-up and inspection in the general or commissioning sections of the mechanical and plumbing design documents.

Air and Water Balance (TAB)

  1. Air and water systems shall be tested including all ducts and fire dampers.
  2. The balancing shall be performed by an independent, certified AABC or NEBB TAB firm.
  3. At least one AABC or NEBB certified balance specialist with a minimum of 2 years’ experience shall be at the site to perform daily TAB activities.
  4. TAB activities shall be reviewed by a certified TAB supervisor or Professional.
  5. Testing and balancing of air systems shall be performed in complete accordance with the latest version of AABC National Standards for Total System Balance, 2002 Edition or NEBB Procedural Standards for TAB Environmental Systems 7th Edition 2005 or subsequent versions.
  6. Balance reports shall be sealed as accurate by a professional engineer licensed in the State of North Carolina.
  7. The designer shall review and approve the qualifications of the balance specialist and the means and methods of testing.
  8. Air quantities shall be balanced to no greater than +/- 5% of design values for research buildings or critical spaces and +/- 10% for other buildings.

The contractor shall provide on-site training to University staff prior to occupancy or acceptance.

For capital projects, contractor shall provide additional classroom or factory training for new Building Automation System, environmental cold rooms, lab air compressors (>50 hp), vacuum pumps (>30 hp), nonpotable water treatment systems, high purity water systems, etc. During design the designer shall specify the appropriate training required through coordination with UNC Engineering Services.

The contractor shall submit training schedules, training syllabus, and resumes of the person(s) giving the training to the University for review and final approval.

The designer shall provide a complete list of all required training in the general or commissioning sections of the mechanical and plumbing design documents.

Training shall not be scheduled until the installation is complete and verified by UNC Engineering Services. Requests for training must be provided to UNC’s training coordinator at least two weeks prior to the event. Requests must include a detailed syllabus, times, names and affiliation of instructors, and a specific meeting location (e.g., room number).

When requested by UNC, the designer shall provide schematic drawings detailing the flow rate and pressure loss for the longest equivalent duct or pipe runs. Diversity factors and other assumptions shall be clearly identified.

When redundant equipment is provided, redundancy levels shall be indicated on the equipment schedules.

When requested by UNC, the designer shall provide an engineering basis of design detailing diversity factors, design velocities, design pressure drops, redundancy values, load calculations, energy model input data, and other criteria used for sizing ducting, piping, equipment, and other components.