Standard for Sound Rating of Large Outdoor Refrigerating and Air-Conditioning Equipment

ARI Standard 370-2001: Essential Guide to Sound Rating of Large Outdoor HVAC Equipment

For engineers designing or specifying large outdoor refrigerating and air-conditioning equipment, understanding and controlling acoustic performance is paramount. ARI Standard 370-2001, the "Standard for Sound Rating of Large Outdoor Refrigerating and Air-Conditioning Equipment," provides an authoritative framework for achieving this. This essential standard ensures that manufacturers and specifiers can consistently evaluate and communicate the sound output of these critical components, mitigating potential noise nuisances and ensuring compliance with environmental regulations.

What is ARI Standard 370-2001?

Developed by the Air-Conditioning and Refrigeration Institute (ARI), this standard establishes comprehensive methodologies for determining and reporting the sound characteristics of large outdoor refrigeration and air-conditioning units. It provides a consistent, proven approach for measuring sound power levels, enabling objective comparisons and informed design decisions for complex HVAC systems.

Scope & Purpose

ARI Standard 370-2001 governs the sound rating of the outdoor sections of factory-made commercial and industrial refrigerating and air-conditioning equipment, including heat pumps. The purpose is to define test procedures, rating requirements, and data reporting criteria to ensure clarity and consistency in acoustic performance specifications. It specifically excludes smaller unitary equipment (under 135,000 Btu/h) and certain types of condensers covered by other ARI standards.

Who Must Comply?

• • Primary audience: Acoustic Engineers, HVAC Engineers, Product Design Engineers, Test Technicians, and Environmental Engineers.
• • Industries affected: HVAC Manufacturing, Industrial Equipment, Building Construction, and Environmental Consulting.
• • Compliance nature: While ARI standards are often voluntary for market access, they are widely adopted and considered best practice, making compliance highly recommended for manufacturers aiming for credibility and market acceptance.
• • Enforcement: Compliance is typically verified through product testing and certification programs, often overseen by industry bodies or regulatory agencies concerned with noise pollution.

Key Requirements Overview

This industry-leading standard mandates a precise approach to sound measurement and reporting. Key provisions include:

• • Comprehensive Sound Descriptors: Professionals must ensure that sound ratings are presented using multiple descriptors, including octave band sound power levels, A-weighted sound power level, and tone-adjusted A-weighted sound power level, all in decibels.
• • Expanded Frequency Range: The standard requires consideration of a broader frequency spectrum, including the 63 Hz octave band, for more thorough acoustic analysis.
• • Detailed Test Procedures: It specifies proven methods for determining sound power levels, often based on sound pressure measurements in quasi-free-field conditions.
• • Fan-Only Operation Rating: The standard extends the rating scope to include sound levels generated by fan-only operation, providing a more complete acoustic profile.
• • Clear Data Publication: Manufacturers are required to publish specific minimum data related to sound ratings, ensuring transparency for users and specifiers.

Related Standards & References

ARI Standard 370-2001 works in conjunction with other critical standards. It references ANSI standards for defining octave and one-third octave bands. Furthermore, it complements standards like ARI Standard 270 (for smaller unitary equipment) and ARI Standards 460/490 (for condensers), ensuring a cohesive