The Indian Society of Heating, Refrigerating and Air Conditioning Engineers (ISHRAE) publishes the Handbook of Air Conditioning, Heating, Refrigeration and Ventilation as its flagship technical reference. The 2024 edition is the latest revision and stands as the Indian-context companion to ASHRAE Handbook series. For Indian MEP designers, knowing what’s in it + when to use it is a practical productivity lever.
This guide covers the chapter structure of ISHRAE Handbook 2024, the topics where it provides Indian-specific guidance that ASHRAE doesn’t, and the workflow for using it alongside ASHRAE.
ISHRAE Handbook 2024 chapter structure
The Handbook is organized into 7 volumes paralleling the ASHRAE structure:
| Volume | Topic | Indian-specific content |
|---|---|---|
| 1 | Fundamentals | Climate data for 175+ Indian cities; ISHRAE TMY weather; HRV/ERV efficiency at high humidity |
| 2 | Refrigeration | Indian refrigerant transition (R32, R454B); CFC/HCFC phase-out timeline |
| 3 | HVAC Applications | Indian projects: hot-humid coastal, composite, mild, cold; healthcare per NABH; cleanrooms per Indian Pharma; data centres for Indian climate |
| 4 | HVAC Systems & Equipment | Equipment selection for Indian climate; chiller comparisons; AHU/FCU sizing rules of thumb |
| 5 | Smoke Control & Fire | Indian-specific NBC 2016 + NFPA + IS 15493 coverage; tenability for Indian high-rise |
| 6 | Building Performance & Sustainability | ECBC 2017 + 2030 trajectory; IGBC v3; GRIHA v2019; net-zero pathways |
| 7 | Emerging Topics | DOAS for Indian climate; chilled beams; demand-controlled ventilation; AI-assisted design |
Each volume is approximately 600-1,000 pages.
Topics where ISHRAE differs from ASHRAE
For Indian projects, ISHRAE provides specific guidance on topics where ASHRAE is US-calibrated:
1. Climate data (Volume 1)
ASHRAE 169 provides climate data for India but resolution is coarse (one data set for “Mumbai region”; one for “Delhi region”). ISHRAE provides TMY3 + TMY data for 175+ Indian cities, including tier-2 and tier-3 locations like Surat, Patna, Bhopal, Coimbatore.
For energy modeling: ISHRAE weather files give 5-15% more accurate results than ASHRAE 169 for tier-2 Indian cities.
2. Hot-humid HVAC strategies (Volume 3)
ASHRAE handbook discusses hot-humid climates broadly; ISHRAE specifically calibrates for:
- Mumbai pre-monsoon (60-70% RH at 35-38 °C)
- Chennai costal year-round (75-85% RH at 28-32 °C)
- Cochin monsoon (90-95% RH at 25-28 °C, with heat-index implications)
DOAS sizing for Indian climate, ERV effectiveness derating in monsoon — these are specifically detailed in ISHRAE Volume 3.
3. NABH compliance (Volume 3)
NABH (Indian hospital accreditation) has specific HVAC requirements that don’t map to ASHRAE 170 directly. ISHRAE Handbook covers:
- OT class definitions per NABH
- Pressure cascade requirements per NABH
- Air change rates per NABH-specific space classifications
- Filtration train per NABH (different from US FGI)
4. Indian fire safety (Volume 5)
NFPA + IS 15493 + NBC 2016 Pt 4 — ISHRAE Volume 5 covers all three jointly with Indian context. ASHRAE Smoke Control Handbook is excellent but US-centric.
5. ECBC compliance (Volume 6)
ECBC 2017 + ECBC 2030 trajectory specific to Indian buildings. LEED + IGBC + GRIHA scoring side-by-side. ASHRAE handbook touches LEED but doesn’t cover Indian rating systems.
6. Refrigerant transition (Volume 2)
Indian Kigali Amendment timeline + manufacturer-by-manufacturer transition. R32 dominance in Indian VRF, R454B uptake by Indian-branded VRF, R290 niche applications.
When to use ISHRAE vs ASHRAE
Use ISHRAE Handbook 2024 when:
- Indian climate analysis (climate data, weather files)
- NABH hospital projects
- ECBC / IGBC / GRIHA compliance
- Indian fire codes (NBC + IS 15493 + NFPA combined)
- Indian refrigerant transition strategy
- Indian project case studies (residential, commercial, industrial)
Use ASHRAE Handbook (still primary) when:
- Fundamental thermodynamics + psychrometrics (ASHRAE Handbook Fundamentals is industry-standard)
- Equipment performance curves at standard conditions
- Indoor air quality (ASHRAE 62.1/62.2)
- ASHRAE 90.1 baseline modeling for LEED
- Cleanroom design (ISO 14644 + ASHRAE Handbook references)
- Data centre thermal envelope (ASHRAE TC 9.9)
Use both jointly when:
- Indian building per international standard (any LEED-targeted Indian project)
- Mixed-use projects with both Indian + international tenant requirements
- Specifications that reference IS + ASHRAE simultaneously
Practical workflow
For typical Indian commercial project:
1. Start with ASHRAE Fundamentals for psychrometric + thermal calculations
2. Apply ISHRAE Volume 1 for site climate data (more accurate)
3. Apply ISHRAE Volume 3-4 for system selection + Indian climate calibration
4. Reference ASHRAE 62.1 + ECBC for ventilation
5. Reference IS 15493 + NFPA + NBC for fire safety per ISHRAE Volume 5
6. Reference ASHRAE 90.1 + ECBC + IGBC + GRIHA for energy + sustainability per ISHRAE Volume 6
What’s missing from ISHRAE Handbook 2024
ISHRAE Handbook is excellent but has gaps:
- No 8760-hour simulation tutorial (use Carrier HAP / OpenStudio)
- No CFD for fire engineering (use NFPA 92 + FDS)
- Limited cleanroom GMP detail (use ISPE Baseline Guide)
- No detailed BIM workflow (use ASHRAE BIM Guideline)
For these, ISHRAE Handbook references the international literature.
Five practical mistakes designers make with ISHRAE
1. Ignoring it entirely. Many designers use ASHRAE only; missing ECBC + NABH guidance leads to compliance failures.
2. Using outdated ISHRAE editions. 2018 or 2022 editions have stale climate data + missing 2024 refrigerant transitions.
3. Treating ISHRAE chapters as primary instead of ASHRAE for fundamentals. ISHRAE adapts ASHRAE; for thermodynamics + psychrometrics, ASHRAE is primary.
4. Reading ISHRAE without ASHRAE in parallel. ISHRAE assumes reader has ASHRAE Fundamentals; reading ISHRAE alone leaves gaps.
5. Not using ISHRAE climate data in energy models. Using ASHRAE 169 generic India data when ISHRAE has site-specific files.
Quick checklist
- [ ] ISHRAE Handbook 2024 (latest edition) accessible to design team
- [ ] ASHRAE Handbook (Fundamentals + Apps) accessible alongside
- [ ] ISHRAE climate data used for energy modeling
- [ ] NABH spaces designed per ISHRAE Volume 3 (not ASHRAE 170 alone)
- [ ] Indian sustainability rating per ISHRAE Volume 6 (not LEED alone)
- [ ] Indian fire codes per ISHRAE Volume 5 + NBC + IS jointly
- [ ] Refrigerant choice per ISHRAE Volume 2 transition timeline
References: ISHRAE Handbook of Air Conditioning, Heating, Refrigeration and Ventilation (2024 Edition); ASHRAE Handbook (Fundamentals 2021, HVAC Sys & Eqp 2024, HVAC Apps 2023, Refrigeration 2022); ECBC 2017 + 2030; NABH Standards 5th Edition.
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