ARI STANDARD 840-98: UNIT VENTILATORS

ARI STANDARD 840-98: UNIT VENTILATORS - AN ESSENTIAL GUIDE FOR ENGINEERS

For HVAC engineers and product designers, understanding the performance and application of unit ventilators is paramount. ARI STANDARD 840-98 provides the essential framework for defining, testing, and rating these critical components of building comfort systems. This authoritative standard ensures consistency and reliability, enabling professionals to specify and implement unit ventilators with confidence.

What is ARI STANDARD 840-98?

ARI STANDARD 840-98, developed by the Air-Conditioning and Refrigeration Institute (ARI), establishes comprehensive criteria for unit ventilators. It defines their purpose, outlines classification methods, and dictates rigorous testing and rating requirements. The primary goal is to provide a standardized basis for performance evaluation, ensuring that manufacturers and specifiers can accurately assess and select unit ventilators for diverse applications.

Scope & Purpose

This industry-leading standard governs factory-made equipment specifically designed as unit ventilators, characterized by their outside air ventilation and return air dampers capable of introducing ventilation air at least 80% of their rated airflow. It dictates requirements for testing, rating, and publishing performance data, including heating, cooling, and air filtering capabilities. The standard explicitly excludes certain types of equipment, such as room air conditioners and central-station air-handling units, focusing solely on the defined unit ventilator category.

Who Must Comply?

• • Primary audience: HVAC Engineers, Product Designers, Test Engineers, Installation Technicians, and Building Managers involved in the specification, design, manufacturing, and maintenance of HVAC systems.
• • Industries affected: HVAC Manufacturing, Building Construction, Commercial Real Estate, and Industrial Facilities.
• • Compliance nature: Voluntary, conformance to this standard is voluntary but highly recommended for product certification and market acceptance.
• • Enforcement: Compliance is typically verified through self-certification by manufacturers and can be audited by third-party certification bodies or referenced by project specifications.

Key Requirements Overview

• • The standard requires manufacturers to define unit ventilators based on their mounting arrangement, capacity control methods, and heating/cooling provision types.
• • Professionals must ensure that unit ventilators are tested and rated under specified "Standard Rating Conditions" to ensure comparability.
• • Key provisions include detailed methodologies for determining the Standard Ventilation Rate, crucial for indoor air quality assessments.
• • The standard mandates specific requirements for electrical conditions during testing, ensuring performance is evaluated at typical operational voltages and frequencies.
• • It also specifies that regularly furnished equipment, such as filters and air-mixing components, must be in place during all performance tests.

Related Standards & References

ARI STANDARD 840-98 works in conjunction with several other ARI and ASHRAE standards. For instance, it references ARI Standards 440, 310/380, 210/240, 320, 325, and 330 for defining specific types of unit ventilators based on their refrigeration system classifications. Furthermore, it relies on ANSI/ASHRAE Standard 79 for the precise determination of ventilation rates, ensuring a comprehensive approach to air quality and system performance.