Development of an Italian Fire Prevention Technical Rule for Hydrogen Pipelines ICHS 2011 - San...

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

Development of an Italian Fire Prevention Technical Rule for Hydrogen Pipelines

DEVELOPMENT OF AN ITALIAN FIRE PREVENTIONTECHNICAL RULE FOR HYDROGEN PIPELINES

N. Mattei, M. Carcassi., N. Ciannelli, F. Pilo

Dipartimento di Ingegneria Meccanica, Dipartimento di Ingegneria Meccanica, Nucleare e della Produzione (DIMNP),Nucleare e della Produzione (DIMNP),

University of PisaUniversity of Pisa

Università di Pisa



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



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 ≤ 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).



Italian Methodology

CCTS

Ministry of Interior

Italian Working Group on Fire

Prevention

Hydrogen

Methane

FIRE PREVENTIONTECHNICAL RULE FOR HYDROGEN PIPELINES

“D.M 16 aprile 2008” (distribution)

“D.M. 17 aprile 2008” (transport)

Experimenthal activity

REGULATION



METHANE SAFETY DISTANCESGauge Pressure

inside pipe [MPa]1° Type

2.4 < P ≤ 62° Type

1.2 < P ≤ 2.43° Type

0.5 < P ≤ 1.2

Categories A B D A B D A B D

Pipe Diameter [mm] Safety Distance [m]

≤ 100 30 10 2.0 20 7 2.0 10 5 1.5

125 30 10 2.5 20 7 2.0 10 5 1.5

150 30 10 3.0 20 7 2.5 10 5 2.0

175 30 10 3.5 20 7 2.5 10 5 2.0

200 30 10 4.0 20 7 3.0 10 5 2.0

225 30 10 4.5 20 7 3.5 10 5 2.0

250 30 10 5.0 20 7 4.0 10 5 2.0

300 30 10 6.0 20 7 4.5 10 5 2.0

350 30 10 7.0 20 7 5.0 10 5 2.5

400 30 10 8.0 20 7 6.0 10 5 3.0

450 30 10 9.0 20 7 6.5 10 5 3.5

> 500 30 10 10.0 20 7 7.0 10 5 3.5



EXPERIMETAL TESTSThe 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



HPBT LAYOUT



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



DISPLACEMENT OF 9 SAMPLE POINTS

x [mm]

y [mm]

z [mm]

X4 290 0 -10

X5 500 0 20

X6 980 0 -10

X7 2000 0 0

X8 2490 0 0

X9 480 0 70

X10 480 0 -50

X11 980 0 100

X12 980 0 -100

HPBT-JR-8

x [mm] y [mm]

z [mm]

X4 620 0 0

X5 930 0 0

X6 2000 320 0

X7 2000 0 0

X8 3060 50 430

X9 2000 -320 0

X10 1230 0 0

X11 2000 0 240

X12

HPBT-JR-19HPBT-JR-8



SUMMARY OF DATAAVAILABLE FOR EACH TEST

angle between wind direction and jet axis

wind velocity

spatial coordinates of sample points

H2 concentration

vs. time



HPBT-JR-8D=2,5mm - P=10 bar

0,00

10,00

20,00

30,00

40,00

50,00

60,00

0,00 50,00 100,00 150,00 200,00

time [sec]

P 1

P2

P3

X4

X5

X6

X7

X8

X9

X10

X11

X12

T1

T2

T3

Start of release

Temperature [°C]inside tanks

Temperature [°C] next to release hole

Pressure [barg]inside tanks

OxygenConcentration

[%vol]

EXAMPLE OF DATA ACQUIRED(Ø 2,5mm and P = 10bar)



0 20 40 60 80 100 120 140 160 180 200-5

0

5

10

15

20

25

30

0

0,5

1

1,5

2

2,5

3

3,5

4

4,5

5HPBT-JR-10 D=5mm P=5,2bar

X4

X5

X6

X7

X8

X9

X10

X11

X12

modulo

tempo [s]

co

nc

. H2

[%

vo

l.]

ve

loc

ità

[m

/s]

DATA ACQUIRED

wind veolcity



JET-FIRE DIMENSION

4 m

0,7 m

Lateral view Front viewØ 11 mm - P 10 bar



JET FIRE DATA ACQUIRED

10

5,5

5

2,2

10,2

6,8

5,6

5,1

2,3

0 0,5 1 1,5 2 2,5 3 3,5 4 4,5 5

Flame length [m]

Internal Pressure [bar]

Ø = 2.5 mm

Ø = 11 mm



CODE SIMULATION - EFFECTS 7.6



CODE SIMULATION - FLACS v9.0 (CFD)



COMPARISON BETWEEN EXPERIMETAL DATAAND COMPUTER SIMULATION

0 500 1000 1500 2000 2500 3000

0

5

10

15

20

25

30HPBT-JR-7 D=2.5mm - P=5.9bar

v=0.7 m/sv=2.1 m/sEFFECTSFLACS 0.7 m/sFLACS 2.1 m/s

time [s]

H2

[%vi

l.]

CENTRAL AXYS [m]



RADIATIVE ENERGY PRODUCED BY A JET-FIREvs.

DISTANCE FROM RELEASE HOLE

0 0,5 1 1 ,5 2 2 ,5 3 3 ,5 4 4 ,5 5

-1 ,5

-1

-0 ,5

0

0 ,5

1

1 ,5

0 1 2 3 4 5 6 70

10

20

30

40

50

60

70

80

90

100

[m]

kW/m

2

[m]

5.4

12.5



Hydrogen and methane radiative powerdue to equal hole and pressure

0 1 2 3 4 5 6 7 8 90

10

20

30

40

50

60

70

80

90

100

[m]

[kW

/m2 ]

5,4 6,8

methane

hydrogen

HEAT RADIATION (EFFECT)



skgw

RT

MAPG max

4

2

4max

2max

CH

H

CH

H

MA

MA

G

G

24 HCH AA

kgMJ

H

kgMJ

CH

molg

H

molg

CH

Q

Q

M

M

120

50

2

16

2

4

2

4

4max4

22max 16

2CH

CH

HH G

A

AG

critic flow mass flow

COMPARISON BETWEEN H2 AND CH4 FLOW

24 HCH QMAQMA

2max4max HCH QGQG

42 2.1 CHH AA

42.1

44

22

2CHH DD

442 1.12.1 CHCHH DDD

energy flow

4max2max )35.0( CHH GG

same area

same T and P same T and P



PROCEDURE FOLLOWED TO DEFINE SAFETY DISTANCE

1. Pipes are categorized as a function of pressure and pipe diameter.

2. A release hole diameter is associated to pipe diameter (Ø hole = 2.5% of pipe diameter).

3. 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



Gauge Pressure allowed inside

pipe [MPa]

1° Type2.4 < P ≤ 6

2° Type1.2 < P ≤ 2.4

3° Type0.5 < P ≤ 1.2

Categories E E E

Pipe Diameter [mm] Safety Distance [m]

≤ 100 3.5 3.0 2.5

125 4.0 4.0 3.0

150 5.0 4.5 3.5

175 5.5 5.0 4.0

200 6.0 6.0 4.5

225 7.0 6.5 5.0

250 7.5 7.0 5.5

300 9.0 8.5 6.0

350 10.5 9.5 7.0

400 12.0 11.0 8.0

450 13.5 12.0 9.0

> 500 15.0 13.5 10.0

PROPOSED SAFETY DISTANCES



THANK YOU.

Contact Author:

Nicola Mattei (UNIPI-ITALY)

[email protected]

Presented by:

Marco Carcassi (UNIPI-ITALY)

[email protected]

Development of an Italian Fire Prevention Technical Rule for Hydrogen Pipelines ICHS 2011 - San...

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