Part 3 of ANSI/IIAR 2-2021 includes chapters 8-18. For the sake of brevity, this blog covers chapters 8-12.
Chapter 8: Compressors
Chapter 8 of the standard for ammonia refrigeration compressors outlines various design and safety requirements. These include provisions for design pressure, compressor protection, pressure relief connections, limiting devices, guarding, rotation arrows, ultimate strength, procedures/testing, equipment identification, compressor installation, and high-liquid-level shutdown. The chapter specifies requirements for nameplates or labels affixed to compressors, compressor installation in low ambient temperatures, use of variable frequency drives, and inspection and recertification of previously used compressors. Additionally, it mandates the fitting of pressure- and temperature-indicating devices and the incorporation of controls to shut down compressors in the event of high liquid levels in vessels to prevent carryover of liquid refrigerant.
Chapter 9: Refrigerant Pumps
Chapter 9 specifies that all refrigerant pumps must comply with the regulations set out in this chapter. There are exceptions for liquid ammonia transfer systems, which must comply with Chapter 12. The design of refrigerant pumps must adhere to specific criteria, including minimum design pressure, protection from overpressure, ultimate strength requirements, protection from rotating parts, suitability for the intended service, and the installation of isolation valves, supports, and foundations. Refrigerant pumps must also undergo strength and leak testing, and be identified with a manufacturer's nameplate. Additionally, pumps must be equipped with a means for ammonia removal.
Chapter 10: Condensers
Chapter 10 discusses the requirements for condensers, including general design requirements for different types of condensers such as air-cooled, adiabatic, and evaporative condensers. The design pressure, ultimate test, leak strength test, and other design requirements are outlined for each type of condenser. The chapter also addresses the protection of isolatable refrigerant and secondary coolant circuits, as well as the required identification on a nameplate or label. Requirements for protection from exposed rotating parts, fan speeds, clearances, freeze protection, and drainage of overflow and wastewater are included in the guidelines for these specific types of condensers.
Chapter 11: Evaporators
Chapter 11 outlines the general design requirements for evaporators, including forced-air evaporator coils, shell and tube evaporators, plate heat exchanger evaporators, double pipe evaporators, scraped (swept) surface heat exchangers, and jacketed tanks. It specifies design pressure, ultimate strength, pressure testing, and leak testing requirements for each type of evaporator. Additionally, it outlines the necessary identification that must be included on a nameplate or label for each type of evaporator. The chapter also includes normative notes related to pressure vessels, protection of isolatable refrigerant circuits, secondary coolant or process fluid circuits, and freeze protection for the products or secondary coolants within the evaporators. Sections 11.2, 11.3, and 11.4 provide specific requirements for fluid freeze protection, design for frozen products, and forced-air evaporator coils, respectively. These sections address installation considerations, protection from exposed rotating parts, fan speed limits, and compliance with chapter 12 for pressure vessels coupled to evaporators.
Chapter 12: Pressure Vessels
Chapter 12 of the document outlines the requirements for pressure vessels. It covers design specifications, including the minimum design pressure and compliance with ASME B&PVC standards. The chapter also details testing procedures, equipment identification, and nameplate mounting requirements. Additionally, it includes installation considerations such as access, physical protection, and support for pressure vessels.
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