DEVELOPMENT OF AN ITALIAN FIRE PREVENTION TECHNICAL RULE FOR HYDROGEN PIPELINES N. Mattei, M. Carcassi., N. Ciannelli, F. Pilo Università di Pisa Dipartimento di Ingegneria Meccanica, Nucleare e della Produzione (DIMNP), University of Pisa ICHS 2011 - San Francisco, USA - September 12 -14

SUMMARY Italian regulation about hydrogen and methane Italian development of regulation Italian Working Group on Hydrogen Experimental facility and tests Data acquired and data elaboration Procedure followed to define safety distance Conclusions ICHS 2011 - San Francisco, USA - September 12 -14

REGULATION IN FORCE IN ITALY Right now no law or technical rule is available to install a pipeline for hydrogen Rules referring to natural gas and and gas with r ≤ 0.8 [kg/m3] must be followed: “D.M 16 aprile 2008” (distribution) “D.M. 17 aprile 2008” (transport) Moreover European laws already cover many aspects involved in design, building and safety issues, e.g. DIRECTIVE 97/23/EC (PED). ICHS 2011 - San Francisco, USA - September 12 -14

Italian Working Group on Fire Prevention Italian Methodology Ministry of Interior REGULATION Experimenthal activity CCTS FIRE PREVENTION TECHNICAL RULE FOR HYDROGEN PIPELINES Hydrogen Italian Working Group on Fire Prevention “D.M 16 aprile 2008” (distribution) Methane “D.M. 17 aprile 2008” (transport) ICHS 2011 - San Francisco, USA - September 12 -14

METHANE SAFETY DISTANCES Gauge Pressure inside pipe [MPa] 1° Type 2.4 < P ≤ 6 2° Type 1.2 < P ≤ 2.4 3° Type 0.5 < P ≤ 1.2 Categories A B D Pipe Diameter [mm] Safety Distance [m] ≤ 100 30 10 2.0 20 7 5 1.5 125 2.5 150 3.0 175 3.5 200 4.0 225 4.5 250 5.0 300 6.0 350 7.0 400 8.0 450 9.0 6.5 > 500 10.0 ICHS 2011 - San Francisco, USA - September 12 -14

to validate the calculation models EXPERIMETAL TESTS The Group has decided to support its work with an experimental activity, by means of a pilot plant named H.P.B.T. (Hydrogen Pipe Break Test) at University of Pisa. The plant has been used to: simulate hydrogen release its ignition and development of combustion. Data have been acquired about: the diffusivity of the gas the dimension of release jet the dimension of jet-fire as function of internal pressure and release hole diameter. to validate the calculation models ICHS 2011 - San Francisco, USA - September 12 -14

HPBT LAYOUT ICHS 2011 - San Francisco, USA - September 12 -14

PARAMETERS OF EXPERIMENTAL TESTS According to the draft, pipelines are categorized as function of internal pressure and diameter. The incidental scenario is defined by: Internal pressure (test pressure: up to 10 bar) release hole diameter/area (2.5 / 5; 5 / 20 and 11 / 95 mm / mm2) Hole diameter and internal pressure have been chosen in order to have a “steady” jet so that it was possible to measure it ICHS 2011 - San Francisco, USA - September 12 -14

DISPLACEMENT OF 9 SAMPLE POINTS HPBT-JR-8 HPBT-JR-8 HPBT-JR-19 x [mm] y [mm] z [mm] X4 290 -10 X5 500 20 X6 980 X7 2000 X8 2490 X9 480 70 X10 -50 X11 100 X12 -100 x [mm] y [mm] z [mm] X4 620 X5 930 X6 2000 320 X7 X8 3060 50 430 X9 -320 X10 1230 X11 240 X12 ICHS 2011 - San Francisco, USA - September 12 -14

AVAILABLE FOR EACH TEST H2 concentration vs. time SUMMARY OF DATA AVAILABLE FOR EACH TEST angle between wind direction and jet axis wind velocity spatial coordinates of sample points H2 concentration vs. time ICHS 2011 - San Francisco, USA - September 12 -14

EXAMPLE OF DATA ACQUIRED (Ø 2,5mm and P = 10bar) Start of release Temperature [°C] inside tanks Oxygen Concentration [%vol] Temperature [°C] next to release hole Pressure [barg] inside tanks ICHS 2011 - San Francisco, USA - September 12 -14

DATA ACQUIRED wind veolcity ICHS 2011 - San Francisco, USA - September 12 -14

JET-FIRE DIMENSION Ø 11 mm - P 10 bar Lateral view Front view 4 m ICHS 2011 - San Francisco, USA - September 12 -14

JET FIRE DATA ACQUIRED Internal Pressure [bar] Ø = 2.5 mm Ø = 11 mm Flame length [m] ICHS 2011 - San Francisco, USA - September 12 -14

CODE SIMULATION - EFFECTS 7.6 ICHS 2011 - San Francisco, USA - September 12 -14

CODE SIMULATION - FLACS v9.0 (CFD) ICHS 2011 - San Francisco, USA - September 12 -14

COMPARISON BETWEEN EXPERIMETAL DATA AND COMPUTER SIMULATION CENTRAL AXYS [m] ICHS 2011 - San Francisco, USA - September 12 -14

RADIATIVE ENERGY PRODUCED BY A JET-FIRE DISTANCE FROM RELEASE HOLE vs. DISTANCE FROM RELEASE HOLE [m] kW/m2 5.4 12.5 ICHS 2011 - San Francisco, USA - September 12 -14

HEAT RADIATION (EFFECT) Hydrogen and methane radiative power due to equal hole and pressure hydrogen [kW/m2] methane 5,4 6,8 [m] ICHS 2011 - San Francisco, USA - September 12 -14

COMPARISON BETWEEN H2 AND CH4 FLOW critic flow mass flow energy flow same T and P same T and P same area ICHS 2011 - San Francisco, USA - September 12 -14

PROCEDURE FOLLOWED TO DEFINE SAFETY DISTANCE Pipes are categorized as a function of pressure and pipe diameter. A release hole diameter is associated to pipe diameter (Ø hole = 2.5% of pipe diameter). The resulting jet fire allows to evaluate the distance beyond which radiative power is lower than a defined value (3 kW/m2 according to Italian laws). (1) (1) D.M. 29 Maggio 2001: following the law, a person can be exposed to such a radiation undergoing to no more that reversible injuries ICHS 2011 - San Francisco, USA - September 12 -14

PROPOSED SAFETY DISTANCES Gauge Pressure allowed inside pipe [MPa] 1° Type 2.4 < P ≤ 6 2° Type 1.2 < P ≤ 2.4 3° Type 0.5 < P ≤ 1.2 Categories E Pipe Diameter [mm] Safety Distance [m] ≤ 100 3.5 3.0 2.5 125 4.0 150 5.0 4.5 175 5.5 200 6.0 225 7.0 6.5 250 7.5 300 9.0 8.5 350 10.5 9.5 400 12.0 11.0 8.0 450 13.5 > 500 15.0 10.0 ICHS 2011 - San Francisco, USA - September 12 -14

Nicola Mattei (UNIPI-ITALY) n.mattei@ing.unipi.it THANK YOU. Contact Author: Nicola Mattei (UNIPI-ITALY) n.mattei@ing.unipi.it Presented by: Marco Carcassi (UNIPI-ITALY) carcassi@ing.unipi.it ICHS 2011 - San Francisco, USA - September 12 -14