Mechanical Equipment Locations

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Introduction

Mechanical equipment proposed for existing and new buildings must meet City of Tacoma Land Use Code, Building Codes, and City Noise regulations. This tip sheet is intended clarify the code requirements, submittal process and best practices of installation to reduce the potential for violations. In all cases, the installation must comply with all City Code and the manufacturer unit listing.

Land Use Code requirements

General Requirements for all Districts.  Mechanical equipment may not be located within a required side yard setback (7.5 feet or 5 feet, depending on zone) or open yard space. Allowances for heat pump units located less than 5 feet from property lines may be considered if meeting all building and noise code regulations. In all cases, chain link fencing, with or without slats is prohibited to use for screening.

Commercial Districts.  Mechanical or utility equipment, loading areas, and dumpsters shall be screened from adjacent public street right-of-way, including highways, or residential uses. Items that exceed 4 feet in height must use fencing, structure, or other form of screening, except landscaping. Items that do not exceed 4 feet above ground level may be screened with landscaped screening. All landscape screening should provide 50 percent screening at the time of planting and 100 percent screening within 3 years of planting.

Multifamily in Residential Districts.  Ground level utilities shall be located and/or designed to minimize their visibility from the street, including highways, and other pedestrian areas and residences.

Roof Top Standards for Commercial, Mixed Use, and Multi-Family Residential Districts.  All rooftop mechanical equipment for new construction shall be screened with an architectural element such as a high parapet, a stepped or sloped roof form or an equivalent architectural feature which is at least as high as the equipment being screened. Fencing is not acceptable.

Building Code requirements

Installation must meet manufacturer’s recommendations, installation requirements, and Code. Common items noted include:

• Heat pumps must not create an obstruction to the means of egress pathways for courts, yards, corridors, and the like. International Residential Code updates will soon require a minimum of 3 feet when part of the means of egress path outside the building. In the cases of commercial buildings and residential with 3 or more dwelling units covered by the International Building Code, the area where the heat pump is located and used for egress may need to be increased.
• Exterior units shall be securely attached to concrete pad or building support. If attached to the concrete pad, then the pad shall be securely attached to the grade. This is commonly completed by rods driven 12” to 18” into the grade at the 4 corners of the pad.
• Electric heat pumps shall be listed and labeled in accordance with UL 1995 per International Residential Code M1403.1 and International Mechanical Code 918.3.

Noise Code

Planning and Development Services is reviewing for locational compliance based on Building and Land Use Codes.  Responsibility for verifying installation is compliant with Tacoma Municipal Code section 8.122 for noise regulations is on the installer and/or owner. The intent of the noise regulations is to not significantly increase sound above existing ambient levels. Heat pumps must maintain no more than 10 dBA above ambient between 7am and 10pm and no more than 5 dBA between 10pm and 7am as measured at or within a receiving property.

Most single-family residential neighborhood ambient noise is near 43 dBA to 52 dBA with higher values near busy streets, industries, and businesses. The table below is general guidance based on the ambient identified above. This will change based on location and variations of neighborhood ambient.

To avoid noise issues, proper location with site specific evaluation by the installer should be conducted to verify the unit does not impact sensitive receivers once installed.

CORRECTING NOISE VIOLATIONS

Equipment found to be in violation of the noise limits can go through additional steps to reduce the noise.

Exterior mechanical unit noise is essentially comprised solely of mechanical noise propagating through the air to nearby receptor locations. The following practices should be considered when installing or retrofitting exterior unit systems:

• Do not place equipment near noise-sensitive receptors.
• Select equipment with lower noise ratings.
• Select fans to operate at peak efficiency.
• Select fan sizes to allow lowest possible motor rate.
• Enclose rooftop equipment in a noise enclosure (provide for adequate airflow).
• Install a noise barrier or parapet wall between the equipment and the receptor. Barriers must break the line-of-sight, have no gaps, and be suitably massive.
• Use acoustical absorptive materials on the source side of a barrier or enclosure.

Plan Requirements for an Heatpump equipment review

Submittal documents:

• A site plan with the proposed location of the heat pump with relation to the existing buildings onsite and adjacent property lines (provide dimensions and distances to property line). The site plan must also show that the unit is not blocking egress pathways (clearly mark the means of egress pathway location and widths).
• Show the unit meets Washington State Energy Code requirements.
• If the unit is conditioning an area in the building that did not previously contain heated or habitable space, then additional submittal for alteration permit is required with the mechanical permit that shows use and compliance meeting Washington State Energy Code requirements.

 Applicable Regulations and References

• Tacoma Municipal Code Section: 06 – Land Use Code
• Tacoma Municipal Code Section: 02 – Building Code
• Tacama Municipal Code Section: 122 – Noise Code
• Washington State Energy Code