Fire Challenges of New HVAC Refrigerants

Transcription

1 2017 NFPA Conference & Expo Fire Challenges of New HVAC Refrigerants Presented by: Bill Walter Climate Controls Security United Technologies Rusty Tharp Goodman Manufacturing Company, L.P. A member of Daikin group What is a Refrigerant A refrigerant is a substance or mixture of substances, usually a fluid, used to provide cooling (A/C or refrigeration) or heating (heat pump). In most cycles it undergoes phase transitions from a liquid to a gas and back again. History of Refrigerants 1 st Generation (1830s to 1930s) Whatever worked (toxic and/or flammable) NH 3, HCs, SO 2, CH 3 CL 2 nd Generation (1930s to 1990s) Safety and Stability (low toxicity, non-flammable) CFCs and HCFCs R-11, R-12, R-22, R-113, R-114, R rd Generation (1990s to 2010s) Ozone Protection (low toxicity, non-flammable) Reduce atmospheric lifetime, remove chlorine HCFCs: R-22, R-123 (Low ozone depletion potential) HFCs: R-134a, R-404A, R-407C, R-410A (Zero ODP) 1

2 The Problem HFC use is being restricted or prohibited Potent greenhouse gases Air conditioning, refrigeration & insulating foams Available alternatives are mildly flammable to flammable Current U.S. codes and standards do not allow these alternates for many applications Rules governing replacement refrigerants could vary by state Why the need for change Ozone Hole Montreal Protocol HFCs CFCs + HCFCs The Rest of the World wants AC&R Source: National Oceanic and Atmospheric Administration (NOAA) Yearly Consumption of HFCs Developing countries Developed countries 2

3 History of Refrigerants 1 st Generation (1830s to 1930s) Whatever worked NH 3, HCs, SO 2, CH 3 CL 2 nd Generation (1930s to 1990s) Safety and Stability (low toxicity, non-flammable) CFCs and HCFCs R-11, R-12, R-22, R-113, R-114, R rd Generation (1990s to 2010s) Ozone Protection (low toxicity, non-flammable) HCFCs and HFCs R-22, R-123, R-134a, R-404A, R-407C, R-410A 4 th Generation (2010s to?) Low Global Warming Potential (Safety and design challenges) HFOs, HFC/HFO blends, natural refrigerants R-1234yf, R-1234ze(E), R-1233zd(E), blends, CO 2, HCs, NH 3 Driving Factors for Change Kigali Amendment to the Montreal Protocol US EPA SNAP Program California Canada EU F-gas regulations Australia Others to come Global HFC Phase-down schedules Montreal Kigali Agreement and F-Gas Agreement Phasedowns Kigali Developed A2 Kigali Developing A5 Group Kigali Developing A5 Group 2 F Gas % 90 93% 90% 90% 90% 80 80% % of Base YearCO 2e Level % 45% 60% 70% 50% 70% % A2 base year , freeze % 30% 21% 20% 15% 20% 15% 10 A5-1 base year , freeze 2024 A5-2 base year , freeze Year 3

4 U.S. Phase-out dates for today s refrigerants Supermarkets Remote condensing units Small vending machines Larger vending machines Stand-alone low temperature Chillers Residential AC, 2024 Unknown, but coming ASHRAE Standards 34 & 15 ASHRAE 34 Safety Classifications Increasing Flammability No Flame Propagation Lower Flammability Lower Toxicity Higher Toxicity A1: B1: CFC, HCFC, most HFCs A2L: B2L: Most HFOs, HFC-32 Ammonia Flammable A2: B2: R152a Higher Flammability Increasing Toxicity A3: B3: Hydrocarbons 4

5 Product Safety Standards Current Status Domestic HVAC UL th edition only allows non-flammable UL th edition permits up to 3 x LFL (A2 & A3) UL st edition only allows non-flammable International HVAC IEC edition 5.1 allows flammable refrigerants with mitigation (small amounts, < 4 x LFL (m 1 ), permitted without mitigation Above m 1 requires detection and circulation / ventilation Additional special requirements for flammable refrigerants include labeling, construction, testing, instructions / manuals, and charge quantity restrictions Product Safety Standards Revisions Status Domestic UL (to be 3 rd edition) will adopt International 6 th edition with modification CANENA WG10 proposal published February 2017 for comments Target is to have STP approval before ICC Code Cycle A submission deadline. International IEC SC61D CDV 348 for IEC th edition passed in January 2017 Modifications in process for FDIS distribution Publication likely in 2018 Product Safety Standards Research Needs AHRTI Research To aid in setting product design and application safety standards and code requirements, AHRI R&T committee formed Flammable Refrigerants Subcommittee (FRS) FRS set out to determine research needs Polled individuals internationally that are associated with standards and code development for what research is needed. FRS developed and prioritized research needs A large handful of higher priority topics are in process. $5+ million funding from DOE/ASHRAE/AHRI/CARB 5

6 AHRTI Research Project 9007 Real Life Leaks Objectives Conduct A2L refrigerant leak and ignition testing under whole room conditions Investigate control limits and safety factors proposed by draft versions of IEC & -89 Determine main effects that affect the severity of 2L refrigerant thermal events Document the refrigerant concentration profiles vs previous CFD models Document any thermal events for future deflagration modeling Investigate other factors that may drive variability or that have been overlooked by safety standards AHRTI Research Project 9007 AHRTI Research Project 9007 Task 1 - testing under a controlled environment A model room built with a standard ISO 9705 size of 3.6m x 2.4m x 2.4m = 20.7 m 3 Various leak rates, heights, oil concentrations, room conditions used. Task 2 testing under a whole room scale Residential AC: split AC in hallway application Commercial AC: rooftop unit and PTAC Refrigeration: self-contained reach-in and walk-in coolers Servicing error and compressor electric feedthrough failure Final report to be released June 2017 AHRTI Research Other Projects AHRTI Research Project 9008 Investigation of Hot Surface Ignition Temperatures AHRTI Research Project 9009 Leak Detector Long Term Reliability ASHRAE 1806 Post Ignition Risk Assessment ASHRAE 1807 Flammable Refrigerant Handling (Service/install) ASHRAE 1808 Assessment of Field-made Joints ORNL Proper Basis for Setting Charge Limits 6

7 Proposed Product Safety Standard UL Detect and mitigate Permit small amounts (< 3 or 4 x LFL, m 1 ) permitted without mitigation Above m 1 requires detection and circulation / ventilation / charge limits Labeling Construction Testing Instructions / Manuals Charge quantity restrictions Or machine room! Proposed Application Safety Standards ASHRAE 15 ASHRAE 15 Addendum d Human Comfort Published PPR1 August 2016 Published PPR2 April 2017 Comments will be addressed in Long Beach Addendum h Machine Room Published PPR1 August 2016 SSPC 15 still evaluating changes prior to PPR2 ASHRAE 15.2P Proposed new standard focused on residential applications Where one system serves one dwelling space Ventilation Requirements SSPC 15 machine rooms requirements per ASHRAE 15 under revision. Addendum h PPR1: A2L charge quantity unlimited Detectors must meet certain requirements Ventilation rate requirements proposed for A2L are inversely proportional to LFL, directly proportional to density, velocity & potential leak area. SPC 15.2 & UL Ventilation rate, in essence, set to eliminate excess charge above 50% of LFL for most circumstances. Varies by product type and installation. 7

8 2017 NFPA Conference & Expo CEUs: To receive CEUs for this session, scan your badge at the back of the room before leaving Evaluation: Complete a session evaluation on the mobile app. (Search app store for NFPA 2017 C&E. ) Handouts: Handouts will be available via the mobile app and at nfpa.org/conference Recordings: Audio recordings of all sessions will be available free of charge via NFPA Xchange. Questions? 8