The IIAR operates as a member-based professional organization. Because their publications are copyrighted technical standards, they are generally not available for free on public file-sharing sites.
Thanks to research funded by ASHRAE and the Ammonia Refrigeration Foundation (ARF), the latest handbook includes a new, reliable method to calculate pressure drop in wet vertical riser pipes. This is the first time such specific data on two-phase ammonia upward flow has been consolidated in the handbook, representing a significant leap forward in the industry's ability to properly design vertical piping.
The piping handbook works in tandem with several ANSI/IIAR standards that you should be aware of: iiar ammonia refrigeration piping handbook pdf link
| Service | Minimum Velocity (fps) | Maximum Velocity (fps) | Reason | | :--- | :--- | :--- | :--- | | Suction Lines | 10 (horizontal) | 4,000 (vertical) | Oil return in horizontal runs | | Discharge Lines | N/A | 5,000 | Noise & pressure drop | | Liquid Lines (non-pumped) | 1.5 | 3.0 | Preventing flash gas | | Pumped Liquid Lines | 3.0 | 7.0 | Maintaining NPSH |
Ammonia systems operate at temperatures well below freezing. Improper insulation leads to ice formation, structural failure, and Corrosion Under Insulation (CUI). This is the first time such specific data
Readily accessible emergency shutoff valves must be mapped out at the perimeter of machinery rooms. 6. Sourcing the Official IIAR PDF
These tables are vital for designing vapor and liquid systems, including flooded evaporators and pumped overfeed risers. Readily accessible emergency shutoff valves must be mapped
Many industrial engineering firms, refrigeration contractors, and technical universities maintain active subscriptions to the IIAR e-library. Check if your institution provides internal portal access to these standards. Summary of Piping Best Practices Piping Phase Key Focus Area Critical IIAR Recommendation Material Selection Use approved carbon steel; strictly avoid copper. Sizing Velocity Control Balance pressure drops against proper oil return. Installation Stress Mitigation Implement expansion loops to handle thermal shock. Safety Leak Prevention
: Aligning industrial practices with national regulations. Key Topics Covered in the Manual
IIAR Membership: Members often receive deep discounts or complimentary digital access to the e-library, which includes the Piping Handbook and various ANSI/IIAR standards.