1、* * v STD-BSI BS EN L20bb-ENGL 1778 1b24bb7 Ob87330 531 BRITISH STANDARD - I- Installations and equipment for liquefied natural gas - Testing of insulating linings for liquefied natural gas impounding areas The European Standard EN 12066 : 1997 has the status of a British Standard ICs 75.200 BS EN 1
2、2066 : 1998 NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW STD.BSI BS EN L20bb-ENGL 1998 1b29bbS Ob87331 478 Amd. No. BS EN 12066 : 1998 Date Text affected National foreword This British Standard is the English language version of EN 12066 : 1997. The UK participation in its
3、preparation was entrusted to Technical Committee GSE/38, Installation and equipment for LNG, which has the responsibility to: - aid enquirers to understand the text; - present to the responsible European committee any enquiries on the interpretation, or proposals for change, and keep the UK interest
4、s informed; - monitor related international and European developments and promulgate them in the UK. A list of organizations represented on this committee can be obtained on request to its secretary. Cross-references The British Standards which implement international or European publications referr
5、ed to in this document may be found in the BSI Stan b) install the c) install the LNG discharge system above the tank, On the SC e) discharge the LNG over the test piece within a period of less than 0,5 s; f) record the tank weight at high frequency for a period of at least 2 min, g) visually inspec
6、t the test rig to ver b) immerse in water for 1 h; c) weigh after draining for 1 h d) immerse in water for one day; e) weigh after draining for 1 h; f) immerse in water for two days; g) weigh after draining for 1 h; h) repeat the last two sequences (fand g) six times. 6.2.2 Parameters derived from t
7、he measurements The water absorption ratio of the insdating lining shail be quantified by calculating the following parameters: a) the water absorption ratio of each test piece after each weighing; b) the maximum value of water absorption ratio of the insulating lining. Annex D specifies the method
8、of calculation of the above parameters. 6 %sting The tests shall be carried out on the three test pieces in order to determine the evaporation coefficient of LNG in contact with the insdating hing under the following conditions: a) the insulating lining is dry as delivered by the manufactureq b) the
9、 insulating lining is saturated with water following immersion for 15 days; c) due to the fact that the insulating material can change its characteristics under the influence of atmospheric agents such as rain, frost, ultra-violet rays etc, it is recommended to determine the evaporation coefficient
10、of LNG after having subjected the insuialmg lining to an ageing procedure. In this case, the ageing procedure shaii be defined by the user and agreed by the insulating manufacturer. The simulated lifetime shail be defined by the user. 7 %st report The results of the tests shall be recorded in a repo
11、rt containing the following information: a) the history of the test pieces before testing, such as storage and hmsportation conditions (temperature, humidiw, etc), time between manufacturjng and testing and conditions of sampling; b) the evaporation coefficient of LNG in contact with the insulating
12、lining in the dry condition (see clause 6a); c) the maxjn-tum value of the water absorption ratio of the insulating lining (see 6.2.2b); d) the evaporation coefficient of LNG in contact with the insulating lining satwated with water following immersion for 15 days (see clause 6b); e) the evaporation
13、 coefficient of LNG in contact with the insulating lining following the accelerated ageing procedure, if requested (see clause 6c). O BSI 1998 STD*BSI BS EN L20bb-ENGL L778 Lb29bb7 Ob8733b T5T = SCALE Page 5 EN 12066 : 1997 Annex A (normative) Specincation of the test rig A.l Description of the test
14、 rig The test rig shall consist of the following (see figure Al): - a tank containing the test piece; - a system of LNG discharge. The materials which are likely to come in contact with LNG shall comply with the requirements of EN 1160. A.2 Specification of the tank The tank shall be designed so tha
15、t its base is a square whose side is between 400 mm and 600 mm. It shall consist of plates of a rigid insulating material forming the sides and base. The test piece shall be sealed onto the base. In order to avoid LNG penetration dong the edges of the test piece and under the test piece, special car
16、e shall be taken when making the joints between the Merent tank components. A.3 Specification of the LNG discharge system The LNG discharge system shall consist of: - a quick tip-over system; - a cover to prevent any LNG splashing; - a hopper to guide the LNG discharge into the tank A.4 Regulations
17、Attention is drawn to existing European Standarb in the field of safety, for example prEN 50145, for the design and operation of the test rig. 1 Test piece / 4 Quick tip-over system 2 Rigid insulation matenai 5 Cover 3 Tightening device 6 Hopper Figure A.l Example of test rig 3 BSI 1998 STD-BSI BS E
18、N LZObb-ENGL I778 LbZtbb7 Ob87337 77b Page 6 EN 12066 : 1997 Annex B (normative) where: Measuring equipment used to determine the evaporation coefficient of LNG in contact with the insulating lining B.l Specification of the scale The scale used to determine the evaporation coefficient of LNG in cont
19、act with the insulating lining shall have the following specification: a) sensitivity 5 x 10-3 kg; b) indicator precision: 5 X lop3 kg; e) frequency of measurement: at least 20 Hz. B.2 Specification of related recorder MO and A are experimental coefficients determined after applying the method of le
20、ast squares to the mass measurements of LNG remaining in the tank as a function of time. C.2 Calculation of evaporation coefficient of LNG in contact with insulating lining The coefficient Ai determined for a test piece referenced i, has the following expression: where: Ai = Kg, PLNG, * (sep + sw, (
21、C.5) The recorder connected to the scale may be of the magnetic or digital tape recording type. Regardless of the type, its data acquisition frequency shall be at least 20 Hz. Annex C (normative) Method of calculation of the evaporation coefficient of LNG in contact with the insulating lining C.l Ca
22、lculation of LNG mass remaining in the tank as a function of time The rate of evaporation Vr(t) expressed in metres per second, as a function of the time (t) that the LNG is in contact with the insulating lining is calculated with a law of the following type: (expressed in ds“) is the overall evapor
23、ation wetted during the discharge (sides and test piece referenced i); is the surface area of an LNG-wetted test piece expressed in m2; is the surface area of the side walls initially wetted by the LNG expressed in m2. is calculated as follows: Kg coefficient of LNG in contact with materials kNG, is
24、 the LNG density expressed in kglm3; Sep Sw, The surface area WL (C.6) Mo, . p = w1 PLNG, sep where: Mo, is the initial mass of LNG discharged over the test piece referenced i expressed in kg; is the perimeter of the test piece expressed in metres. (C. 1) Kr Vdt) = -$ where: p Kr is the evaporation
25、coefficient of LNG in contact with the insulating lining expressed in ds“. Coefficient Kg, has the following expression: * Kw SW se .K + Consequently, the variation in the mass of evaporated K- LNG, q, is expressed as a function of time by a gi - sep +“s,. epi sep +iWi 1 UI law of the following type
26、: where: is the evaporation coefficient of LNG in contact with the insdating lining of the test piece referenced i expressed in m/s%; is the evaporation coefficient of LNG in contact with the tank walls, determined in C.3 expressed in ds“. (Ca Ue(0 - A dt -$t where: K, Melt) is the mass of evaporate
27、d LNG expressed in kg; A is a dimensional constant determined experimentally expressed in kg/s“. The evaporation coefficient of LNG in contact with the insulahg lining of the test piece referenced i, is expressed as follows: Consequently, the LNG mass M(t) remaining in the tank is expressed as a fun
28、ction of time by the following law: PLNG sep sep -% .Kw (C.8) Ai K= M(t) = MO - Me(t) M(t) =Mo- 2A 4 (C.4) (C.3) O BSI 1998 STD.BSI BS EN L20bb-ENGL 1998 lb2Libb9 Ob87338 822 Ai in kg/“ PLNG in W3 Kepi in m/s% Swi in m2 The evaporation coefficient of LNG in contact with the insulating lining Kr is t
29、he mean value of the coefficients calculated for each of the three test pieces: 0,0131 0,0136 0,0145 453,7 453,7 453,7 17,s x 10-5 17,93 X 10-5 19, x 10-5 0,0137 0,0153 0,0149 C.3 Calculation of evaporation coefficient of LNG in contact with tank walls The evaporation coefficient of LNG in contact w
30、ith the test piece referenced i of the same material as the tank walls is expressed as foliows: K= Ai (C.10) PLNG, . (Sep + swi ) wi The evaporation coefficient of LNG in contact with the material of the tank walls Kw is the mean value of the coefficients calculated as follows: (C. 11) C.4 Example o
31、f calculation The tests described below were performed with three square test pieces having the foliowing dimensions: - side: 400 nun; - thickness: 70 nun; - surface area: 0,16 m2. The weight of the LNG discharged over the test piece was measured by means of an electronic scale taking readings every
32、 50 ms for 2 min. The tank walls were made of polyurethane. Hence, the K, coefficient has a value equal to 0,83 X Table C.l indicates, for each test piece referenced i, the values of the following coefficients and physical parameters: m/s%. - the dimensional constant A, determined according to a law
33、 of the following type, after applying the method of least squares to the measurements of the LNG mass remaining over the test piece in the tank as a function of time: - the LNG density, bGL; - the surface area Swt of the tank walls iniWy wetted by the LNG - the evaporation coefficient of LNG in con
34、tact with the insulating lining, Kept. M(t) =Mo - 2Ai+ (C.12) Page 7 EN 12066 : 1997 The evaporation coefficient of LNG in contact with the insulating lining K, is: 17,s + 17,93 + 19,19 10-5 mls/i 4= 3 K, = 18,151 X m/s“ C.6 Bibliography Emission and dispersion. Chapter 15 In: Frank F? Lees, ed, Los
35、s prevention in Ute process industries. Liquids spills on the ground - Spreading and evaporation. Chapter 6 In: Torstein K. Famelp, ed., Fluid mechanits for industrial safety and envimmental p?vtection. MCNAUGHJDN, D.J., and C.M. BERKOWPZZ. Heavy gas and risk assessment. In: Harhyig, ed., Overvim of
36、 US. research activities in Ute dispersion of dense gases. SHAW i?, and E BRISCOE. Evuporatim from spills of hazardous liquids on land and watm SRD, ed. Annex D (normative) Method of calculation of the water absorption ratio of insulating lining D.l Water absorption ratio of a test piece after immer
37、sion The water absorption Mo, Pr, after an immersion time, t, of a test piece is given by the foilowing formula: *t - mo P= rt m0 where: mt is the mass of the test piece after immersion time t and after 1 h of dripping, on a flat surface; is the mass of the test piece before the first immersion. mo
38、Table C.l Values of coefficients and physical parameters required for the calculation of the evaporation coefficient of LNG Reference of the test piece I 1 12 13 O BSI 1998 STD-BSI BS EN L20bb-ENGL 1798 Lb24bb b87339 7b Reference of the test piece 1 Page 8 EN 12066 : 1997 2 13 D.2 Maximum value of t
39、he water absorption ratio of the insulating lining D.3 Numerical example The table D.l defines for each test piece: lh 1 day 3 days 5 days 7 days The value of water absorption ratio of each test piece determined experimentally as a function of immersion using a law of the foilowing type: aitz + bit
40、- the weight, q, before the first immersion; - the weghts after each immersion and the ii-ne SM be adwted by the least squares method by corresponding values of the water ratio P ; ci7 4; t (Da - the values of the a function Pri (t). 10,61 + 10,28 + 9,55 % ai, bi, ci, di are the adJustment coefficie
41、nts of the - - 3 The maximum value of the water absorption ratio for P., = 10,15 % the test piece referenced i is: 9 days 11 days 13 days 15 davs The maximum value of the water absorption ratio for the insulating lining is the following: 39,27 9,08 39,18 8,82 38,87 7,98 39,35 9,30 39,25 9704 38,95 8
42、,21 39,46 9,60 39,36 9,32 39,06 8,51 39,41 9,47 39,31 9)20 39,02 8738 bi i di Prmq Immersion duration 221,Ol 220,58 218,89 60,90 60,62 69,87 - 7,36 1709 -0,62 10,61 10,28 9,55 I m, I p., I mt I mt I I I I a; I 10,61 I 10,28 I9,55 O BSI 1998 STD-BSI BS EN L20bb-ENGL 1998 W Lb211bbS Ob873110 1180 W BS
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