Maritime transportation of containerized cargo. Part V: Fire tests in a closed aluminium container

NEDERLANDS SCHEEPSSTUDIECENTRUM TNO

NETHERLANDS SHIP RESEARCH CENTRE TNO

ENGINEERING DEPARTMENT LEEGHWATERSTRAAT 5, DELFT

*

MARITIME TRANSPORTATION

OF CONTAINERIZED CARGO

PART V

FIRE TESTS IN A CLOSED ALUMINIUM CONTAINER

(CONTAINERVERVOER PER SCHIP)

DEEL V

(BRANDPROEVEN IN EEN GESLOTEN ALUMINIUM CONTAINER)

by

ING. H. J. SOUER

lechnical Centre for Fire Prevention TNO)

RESEARCH COMMITTEE: W. N. BESSEM DR. J. F. VAN ELTEREN J. N. F. LAMEIJER ING. H. J. SOUER A. P. VtSSER

IR. A. VAN DER WOUDEN

IR. A. DE Moo (ex officio)

Gezien de vrij ingrijpcnde wijzigingcn die zich de laatste jaren hebben voltrokken over de wijze waarop en de middelen waar-mee het goederentransport over zee plaatsvindt, is het eens te meer van belang zich rekenschap te gcven van de regels en bepa-lingen. die betrekking hebben op de veiligheid van bemanning, schip en lading.

Met name de klassifikatiebureaus, scheepvaartinspekties en andere wetgevende c.q. raadgevende instanties zijn hier sterk bu betrokken.

Een van de meest gevreesde kalamiteiten, die zieh aan boord van een schip kan voordoen, is ongetwijfeld het uitbreken van brand.

Met het oog hierop zijn ten aanzien van de bouw van het schip, de gebruikte materialen en de stuwage van de vervoerde goederen

stringente regels van kracht.

Wijziging van de vervoerstechnieken vraagt om herziening van de geldende regels. In dit verband wordt gedacht aan het

con-tainervervoer.

Omdat gemeend werd dat bu het opstellen van aan het con-tainervervoer aangepaste regels de met konventionele vervoers-technieken opgedane ervaringen niet toereikend waren, werd besloten tot de uitvoering van een aantal experimenten. Het doel van de proeven was meer inzicht te krijgen in de vraag hoe lading en container zich zullen gedragen bu het n brand geraken van in een container geladen goederen.

Begonnen werd met bet onderzoeken van containers van plywood eri van staal. De opzet en uitkomsten van het onder-zoek zijn vastgelegd in rapport no. 177 M, dat door bet NSS werd samengesteld. Voorstellen voor een vervolgonderzoek re-sulteerden in ceri serie proeven waarbij gebruik gemaakt werd van een container van aluminium.

De resultaten van dit onderzoek bevestigen het in eerderge-noemd rapport gestelde nl. dat ingeval van brand in een container de risiko's voor bemanning. schip en overige lading klein, zo niet nihil, zijn in vergelijking tot overeenkomstige lading, die op de konventionele wijze per schip wordt vervoerd.

Nog dient bet voorbehoud gemaakt te worden dat de konklu-sies slechts gelden voor gesloten containers van plywood, staal en aluminium die geladen zijn met "gewone" brandbare stoffen, zoals papier, bout, enz. en onder bepaalde voorwaarden wan-neer brandbare vloeistoffen in het geding zijn.

Voor een verdere evaluatie van de problematiek worden nog enkele suggesties gedaan voor nader onderzoek.

Vertrouwd wordt dat ook dit rapport, dat als een vervolg op voornoemd rapport 177 M moet worden beschouwd, eveneens zinvol zal kunnen bijdragen aan het overleg tussen de betrokken instant ies.

NEDERLANDS SCHEEPSSTUDIECENTRUM TNO

In view of the drastic changes, over the l960s and l970s, in the ways and means for deep-sea transportation of cargo, rules and regulations with regard to the safety of crew, ship and cargo are being revised. In particular classification societies, national authorities and other legislative and consultative organizations are involved in updating these rules and regulations.

One of the most dreaded calamities on board ship is the out-breakofa fire. Therefore, the design and construction of a ship, the materials used and the cargo storage are bound to stringent rules.

In the present revision of rules, reference is made to container-ization; a method of cargo transport which today is almost common practice.

It was felt that experience gained with conventional transporta-tion systems would not suffice to draft appropriately adjusted rules, and it was therefore decided to first carry out some experi-ments enabling better understanding of the behaviour of both cargo and container under the influence of an internal fire.

The experimental work started on containers of plywood and steel; it is described in detail in our Report no. 177 M. The underlying report describes fire tests carried Out in a closed aluminium container.

The results of this investigation confirm those of the earlier report, viz, that in the event of fire the risks for crew, ship and remaining cargo are limited, if not nil, when compared to

similar cargo transported with conventional dry-cargo ships. These conclusions, however, are only applicable to closed containers of plywood, steel and aluminium when loaded with such "ordinary" combustibles as paper, wood, etc. and, under certain conditions, with flammable liquids.

Suggestions for future work are given.

lt is hoped that this report, together with Report no. 177 M, will be a valuable contribution to the discussions among all parties concerned.

Summary

CONTENTS

page I Introduction 5 2 Experimental work 5 2.1 Fire tests 5

2.1.1 The container under investigation 5

2.1.2 Method used 6

2.1.3 Description of fire tests 8

2.1.4 Results 9

2.2 Measurement of container leakage 12

2.2.1 Introduction 12

2.2.2 Methcd used 13

2.2.3 Results 13

3 Discussion of results 1 3

3.1 Fire tests 13

3.!.! Fuel used: woodcribs ¡3

3.1.2 Fuel used: flammable liquids 14

3.2 Container leakage 14 4 Conclusions 14 4.1 Leakage 14 4.2 Aluminium construction 14 4.3 Floor 14 4.4 Fuel 14 4.5 Risk ¡4

5 Suggestions for future work 1 5

6 Acknowledgements 15

i

Introduction

The investigations described in this report are a

con-tinuation

of those

described in internal reports

BV-72-60 and BV-72-80 of the Technical Centre for

Fire Prevention TNO (not published). The present report is further to Report no. 177 M, dated April

1973, published by the Netherlands Ship Research

Centre TNO [1]

In chapter 5 of ref. [1], the following recommenda-tions for future work were made:

Fire tests in steel containers having a leakage of

more than 420 m3/secxlO3 at 1000 Pa

over-pressure. If under these conditions self-extinction

will occur it may be concluded that use of steel containers will involve no or hardly any risks.

Aluminium containers, too, should be subjected

to similar fire and leakage tests. lt might be possible that their walls melt under the influence of a fire in a container, such because of a rapid growth of fire. The said three types of containers should internally be subjected to liquid fires. A distinction should be

made between liquids having a flash point high above the temperature in the container and liquids

having a flash point below it. The first group may show a growth of fire that is very much the same as that for solid combustibles. The second group

may lead to explosions of vapour-air mixtures.

What might happen when a burning liquid leaks

out of a container may also be regarded as a subject

for further tests. In this respect, the fire resistance

MARITIME TRANSPORTATION OF CONTAINERIZED CARGO

PART V

FIRE TESTS IN A CI.OSED ALUMINIUM CONTAINER

by

[ng. H. J. SOU ER

Summary

In order to get an idea of the behaviour of a container in case its cargo catches fire (regardless of the cause) and of the possible risk for adjacent containers, and, implicitly, the hazards for the ship's crew, experiments have been carried Out.

The experimental work started with a series of fire tests in arbitrarily chosen containers of different constructions (plywood and steel). As cargo were used small quantities of wood, this being considered an ordinary combustible. The test results and considerations are published in Report no. 177 M, dated April 1973.

In view of the suggestions offered in that report, a second series of fire tests has been set up concerning the behaviour of a slightly damaged aluminium container if inside the container certain liquids catch fire.

The results indicate that the risk for ship, and remaining cargo, when the cargo of one container catches fire, even when the cargo consists of bottled liquids with a fiashpoint sufficiently higher than the ambient temperature - the container loaded with these sub-stances should then have a certain floor construction - is rather limited: it is even considerably lower than the fire risk on board conventional dry-cargo ships.

Recommendations are given for future work.

of containers subjected to external fires is of

im-portance. The fire resistance of several types of containers subjected to external fires should, there-fore, be determined.

The fire risk in containers loaded with commodities that are liable io undergo self-heating and with

those that can burn without oxygen supply, etc., is another important aspect. Tests with this kind of

cargo are either difficult, or impossible, because of the dangerous character of the experiments

in-volved.

As far as self-heating is concerned, it may be said

that the smaller the cargo the safer; the advantages

of a container thus loaded over cargo in bulk are

obvious.

The investigations carried out as described in the

underlying report focus on points 2 and 3; they partly relate to point 4.

The fire tests were done by engineers of the

Techni-cal Centre for Fire Prevention, which is a branch of

the Institute TNO for Building Materials and Building Structures, Rijswijk near The Hague (Netherlands).

The leakage measurements were carried out by

engineers of the group for Building Constructions of the same TNO-institute.

2 Experimental work

2.1 Fire tests

2.1.1

The container under investigation

The aluminium container we investigated was one

* Numbers in parentheses designate references at the end of the

6

Fig. I. Detail of damaged side-wall of the aluminium container.

(integrated in the Nederlandse Scheepvaart Unie); it had not been used for some years because of its dam-aged condition. Its damdam-aged parts, viz, open seams

in a deformed wall and deformations of the steel frame,

were considered to be slight in view of the aim of the

investigations. See fig. I.

The rate of ventilation of aluminium containers will probably never exceed that of the container under investigation.

The container was of the 20-ft type and marked VNS Rotterdam 210007. Concerning its construction,

the certificate stated the following particulars: "Single-wall metal container. Metal frame, metal walls, roof and doors, and locking mechanism fitted with bolts and welded nuts and bolts".

The inside of the innerwalls of the container were not provided with ceiling boards. Its outside dimen-sions were 6050 mm x 2430 mm x 2430 mm, and its

cubic capacity about 31 m3.

There were no special ventilation openings. The thickness of the material of the folded walls was ca. 2.5 mm. The boarded floor had a thickness of38 mm. The

boards had an effective width of 143 mm and were joined by groove and tongue. Seams of sonic

milli-meters wide could be observed in the floor.

Before testing, the doors of the container and their locking system had to be overhauled, so that shutting

could be normal; damaged parts in walls and roof,

e.g. some cracks and the like and slight deformations,

were left as they were.

2.1.2

Method used

As described in Report no. I 77 M, a certain quantity

of combustible material can be burnt in an enclosure. The container in question should thus be tested when

inside it certain combustible liquids were catching fire. To compare the results obtained with regard to containers ofplywood and steel with those of the

alu-minium container, the first part of the investigation has been carried out by using standard wood cribs.

These cribs and their igniting source are described in detail in ref. [1]. lt may be remembered that each crib is built up oflayers of lathwork (see fig. 2). Each layer consists of six parallel laths of fir (10 mm x 25 mm x400 mm) with a spacing of 50 mm; 40 layers

cross-wise cemented together form a crib. Its dimensions

were 400 mm x 400 mm x 400 mm and its weight about 11.5 kg. A number of fibre board strips sprinkled with methylalcohol, and ignited by an electric filament, were used as igniting source.

In the second part of the investigation, which was

the most significant, flammable liquids were used. For reasons of safety, the liquids applied should

have flash points that are sufficiently higher than the

ambient temperatures.

- The flash point of a liquid is the lowest temperature at which it gives off a vapour sufficient to form an

ig-riitible mixture with the air near the surface of the

liquid, in other words: the lower flammability limit is

reached. Some spark or flame is necessary to get

ignition.

-In the case in question, the ambient temperatures

did not rise above 10°C; as flammable liquids have been chosen kerosine for the first series of part two

and butanol, ethylene glycol and xylene besides kerosine for the second series.

In the first series of tests, the influence was observed

that kerosine, when poured on the floor and ignited, might have on the container. These tests simulated a

leaked flammable liquid when ignited regardless of the

cause. Special observations were made with regard to

the behaviour of the floor construction.

In the second series of tests, the influences of the different liquids on the container construction, after ignition of a certain amount poured in a steel tray and

provided with some cotton waste, were compared. Furthermore, the maximum amounts of the used

liquids which could burri out in the closed and empty

container were observed.

Ignition of the liquids occurred in the same way as applied to the wood cribs.

During the tests, the temperatures, the pressure and

the oxygen content within the container were measured

and the deformation of the walls and roof observed. Two thermocouples were used and connected with a millivolt recorder. One couple, near the base of the fire, indicated the duration of the fire, the other one

the temperatures near the roof above the fire. The

Table 1. Results of the most significant tests.

wires were led through small openings in a sidewall;

after mounting the wires, the openings were sealed. For measuring the pressure inside the container, two instruments were used. One of these was a U-tube

filled with a special liquid for direct reading and the other one a device based on induction (alteration of pressure results in alteration of induction) and con-nected to a millivolt recorder. Both instruments were connected to a socket mounted in the side-wall.

For measuring the oxygen content of the atmosphere inside the container, particularly during the successive stages of the fire, an oxygen analyser based on the

property of paramagnetism of oxygen, was used and connected to a recording instrument. The samples of

gas were taken near the base of the fire at 0.2 m above floor level and led to the analyser via a thin brass tube that passed through the side-wall.

The deformations of roof and walls were observed

X = xylene

investigation fuel and waste cotton igniting source some test results

fibre

board contents

strips of _maximum

fuel cotton 100mm2 oxygen pressure

serial total methyl fire consump-at end

number kind weight form location length alcohol stopped tion of of test rise drop part series of test 1) _{quantity (kg)}

) of fire (mm) (ml) by 3) fuel (°) (Pa) (Pa)

I W 11.5 kg

-

onthefloor 140 200 E 5 kg 11.5 50 0 2 W 23 kg - do 140 120 0 8 kg 8.5 300 250 3 W 11.5 kg

-

do 140 100 0 5 kg 4 W 11.5kg - do 140 200 E e--5 kg 11 1 7 K 1.51 0.2 K do 140 150 E 1.51 100100 2a 8 K 0.1 I 0.1 K in tray 8B 20 20 F 0.1 I

-

80 40 9 K 0.5! 0.1 K do 20 20 F 0.5 I

-

240 80 IO K I I 0.1 K do 20 20 F I

-

800 560 Il K I I 0.2 K do 20 20 F ¡ 250 100 12 K I 1 0.1 K do 20 20 F I I

-

1100 1550 13 K 1.51 0.1 K do 20 20 0 <1.51

-

1600 1600 14 K 2 I 0.1 K do 20 20 0

-

1450 1400 15 K I I 0.1 K do 20 20 F 1 1 17.6 460 460 16 K 2 I 0.1 K intray2lB 20 20 0 19.4 420 40 2b 17 K 2 0.1 R do 20 20 0 16.4 2450 2550 18 K 2 0.1 R intray8B 20 20 0 -1.51 15.0 1400 1200 19 K 2 0.1 R do 20 20 0 1.51 - 1200 1530 20 E 2 0.1 R do 20 20 F 2 1 15.5 500 580 21 B 2 0.1 R do 20 20 F '-2 I 15.7 900 1220 22 X 2 0.1 R do 20 20 0 1.51 16.4 2000 2000 23 X 2 0.2 R intray2lB 20 20 0 -1.5I 15.5 3600 3400 24 B 3 0.2 R do 20 20 0 2.5! 16.2 3200 2350 25 E 3 0.2 R do 20 20 0 -2.7 1 16.2 2150 1450 2c 26 K 2 1 0.1 L in tray L 20 20 0 -1.5 I 27 K 2 I 0.2 R in tray 21 B 20 20

0

-1.5 1

1) _{W = wood}

_{) K=knot}

3) _{E extinguishing}

K = kerosine R = ring O = decreased oxygen content

E = ethylene glycol L = longitudinal F = lack of fuel

8

visually in order to decide if any significant permanent deformations should occur.

The consumption of wood was determined by

weighing the cribs before ignition and their residue after the burning had stopped.

The consumption of liquid was determined in the

same way by means of a measuring glass.

In some parts of the report, e.g. in tables. the wood, combustible liquids and so on are grouped together as "fuel".

2.1 .3 Description of fire tests

Table no. I summarizes all the tests of any importance that have been carried out. They are divided in the

parts explained below: Part I, Part El series 1, Part 11

series 2a, 2b and 2c.

Part I. Tests with wood cribs

The cribs of wood were placed on the floor as follows:

Tests I and 4:

In the middle of the floor. Besides the normal igniting source a more or less arbitrary amount of methyl-alcohol had been sprinkled on the floor around the

crib. In Test I the amount was not wilfully sprinkled

but more or less spilled; in Test 4 sprinkling was wilful. Test 4 should be considered as a repeat of Test 1.

Test 3:

in the middel of the floor. No methylalcohol was sprinkled or spilled upon the floor round the crib. This

test was set up in the first place to compare the

influ-ences of amounts of ignition fuel sprinkled around the cribs as in Test I.

Test 2:

In one corner of the container. Two cribs were used; stacked together and placed on a blanket of mineral wool covered by a metal sheet to protect the wooden

floor from fire.

Two cribs were placed against a side-wall and the front to obtain intense heating of the aluminium walls and roof.

Part II. Tests with flammable liquids

Series 1, Test 7:

Kerosine as a flammable liquid. Some kerosine was poured out on the middle of the floor to simulate a certain amount of liquid leaked from a bottle.

For easy ignition of the kerosine, some waste cotton was added to the moistened place. Finally, the electric

igniting source was placed upon the soaked cotton.

Series 2:

As a consequence of the results obtained with flam-mable liquids spilled or sprinkled on the floor and

ig-nited, the next tests were carried out by applying steel trays in which the fuel was poured. The steel trays

protected the floor against fire while the purpose of

these tests was to observe the growth of fire in the container and its influence on the construction.

Series 2a:

The steel tray (marked 8B) primarily used for

nor-malized research on portable extinguishers, had the

following dimensions:

diameter

560 mm

depth 100 mm

thickness of the wall

2 mm

area 0.251 m2

In the middle of the tray some waste cotton was

placed:

it could absorb some liquid and on it the

igniting source was led (see also fig. 3).

Fig. 3. Steel tray 8B with waste cotton knot.

Tests 8 7.

15:

At the beginning of these tests, the quantity of kerosine

was varied from 0.1 I to 2 I. The quantity of waste

cotton amounted to 0.1 kg (0.2 kg in Test Il).

Test 16:

In this test a steel tray, marked 21 B, was used into

which 2 1 of kerosine was poured.

Series 2b, Tests 17 7. 25:

Besides tray 8B another one of the same type, marked

21B, was used: ¡t had the following dimensions (see

Fig. 4):

diameter

910 mm

depth 150 mm

thickness of the wall

2 mm

Fig. 4. Steel tray 2]B with a ring of waste cotton.

The influence of the increase in area (from about 0.25 m2 to 0.66 rn2) on the growth of fire and,

in-directly, on the container construction could thus be

observed.

The waste cotton, 0.1 kg or 0.2 kg in weight, was placed in the form of a ring leaving some distance to

the wall. The four chosen liquids were applied in both trays. Some particulars of the liquids are given in

Table li.

Table II. Some data of the used flammable liquids.

flash point calorific value liquid C kcal/kg

The fire tests were carried out at ambient temperatures

between 5 and bC. Therefore, the flammable liquid,

i.e. xylene, was considered to be a safe one.

Series 2c, Tests 26 and 27:

These additional tests were done to subject the walls and the roof to higher temperatures than those

ob-served in the previous tests. The behaviour of the con-struction, especially that of the aluminium parts, could be better evaluated.

In Test 26 use was made of a rectangular steel tray (marked L) length 1000 mm, width lOO mm, depth

50 mm, filled with 2 1 kerosine and 0.1 kg waste cotton

that was laid lengthwise in the tray.

This tray had been placed on the floor near and along a side-wall.

Flames could heat part of the aluminium wall

directly.

In Test 27, tray 21B, filled with 2 I kerosine and

0.2 kg waste cotton, was placed upon a I ni high stack of stones piled up on the floor of the container. Flames

could heat part of the aluminium roof more directly than in the previous tests.

2.1.4

Results

The results of all tests are described below, arid the most characteristic results are presented in diagrams (see Figures 6, 8, 9, 10, 11).

Part I, Tests ¡ /. 4

Test i

The wood crib, 11.5 kg, was placed in the middle of the floor. After ignition, the process of combustion

was slow; it showed no important difference with that

observed in previous work.

Because of the slow combustion, the changes in pressure were slight.

Fire penetrated through a seam in the floor just under the crib 45 minutes after ignition.

Under the influence of the ambient air (in the be-ginning slight, later more), combustion proceeded. After some 50 minutes, the container was opened and the fire extinguished so that damage to floor and con-tainer was restricted within certain limits. The floor

had been tightened by means of a plate of wood.

Penetration of fire must be ascribed to rather wide

seams in the floor through which could seep the igniting

liquid. This liquid caught fire, and set fire to parts of

the floor.

Test 2

To get a more intensive heating of walls and roof, two wood cribs, 23 kg of weight were stacked together and placed in one corner in front of the container.

To protect the floor from any fire of the igniting

liquid, sheets of mineral wool and steel were led

be-tween cribs and floor.

After ignition, combustion was faster than in the foregoing test; it was a process similar to that in the containers of plywood and steel. The floor remained free from fire.

The influence of the fire upon the walls and roof

was only some discolouration of the material bui the construction itself remained intact (see Fig. 5).

The results of Tests I and 2, in terms of tempera-tures, pressures and oxygen contents, are shown in

Fig. 6.

Test 3

As a consequence of the results of Test 1, the wetted

ignition strips and the like were carefully placed in the base of the crib.

The fire appeared similar to that which may be

considered normal. lt died out from lack of oxygen.

kerosine 51:) II .100

ethylene glycol 40 5.870

butanol 35 8.500

lo

Fig. 5. The two wood cribs, after completion of Test 2. Note the discouloration of the container walls.

Although the crib covered some seams in the floor,

none of the floor was affected by the fire.

The consumed quantity of wood showed that

com-bustion took place in the manner to be expected.

Test 4

To demonstrate that a flammable liquid leaked or

wilfully spilled must be the cause of fire penetration

through a floor with seams, even when wood cribs were used, an amount of 200 ml ethylalcohol was

sprinkled around the base of the crib.

Crackling of burning wood could be heard 1 5

min-utes after ignition, while smoke escaped through the

seams in the floor just under the crib (see Fig. 7).

Fig. 7. Burned part of the container floor, after fire penetration resulting from spilled ignition liquid.

Flames penetrated through these seams 24 minutes

after ignition. Some minutes later the doors of the container were opened and the growing fire was extinguished.

Should the fire not have been extinguished in time,

the leak of the container would have intensified.

In the case of a loaded container on board ship, the contents would soon be exposed to a rapidly growing fire. The burning container as a whole would then a

danger to adjacent containers, goods, etc.

With a view to further tests, the floor was repaired

by means of a plate of wood.

Part Il, Series I

Test 7

To determine once again the effect of a burning liquid

on the floor of the container in question, 1.5 i kero-sine was poured on the floor; part of it was absorbed

Fig. 6. Results of Tests i and 2.

-1000 _,-10 -18

16

o s 1,2 1,2 Trof i 2 ire Pressure 1,2 -1g 21

:

L) 3-E û--500 +1000

-by 0.2 kg waste cotton and fibre board strips placed

on the floor.

Ignition cccurred in the usual way and within one

minute the kerosine was burning fiercely. The pressure in the container increased by 900 Pa and flames pierced

through seams in the floor.

The floor caught fire 2 minutes after ignition; ex-tinguishing was started immediately thus preventing the container from being lost.

This result confirms those obtained in Tests I and 4, where besides the wood crib small quantities of a flammable liquid had been involved.

Series 2a, Tests 8

/. 16

These tests were an introduction to Tests 17 et seq. The

effects of increasing amounts of "fuel" on the growth

of fire were observed.

To protect the floor, and to get a better

reproducibil-ity of the tests, use was made of steel trays (type 8B

and 21B). See also Table!.

Burning stopped completely and suddenly after oxygen contents had decreased to l5l64, normally

reached within 10 minutes after ignition.

The fire was generally the most intense during the

first few minutes after ignition. This could be seen through a small opening provided with a pane of mica: it was also concluded from the measured temperatures and changes in pressure.

1f the process of combustion was slow, as e.g. in Test 11, pressure changes were rather low; the fuel burned after a bad ignition on the wick formed by the waste cotton. lt was found impossible to burn more kerosine than about 1.5 1 in the closed container.

Sorne particulars about the trays

The bottoms of both trays were somewhat bulgy as a

result of frequent use during earlier experiments. Fuel

that was poured above the middle of the bottom

+1000

flowed to the walls, leaving the soaked cottonknot in the middle of the tray, or a moistened surface in the soaked cotton ring, and causing a kind of plash just

near the walls of the trays.

Series 2b, Tests 17

7. 25

These tests should be considered the most important

of the investigation.

As is shown in Table 1, use was made of the two

types of trays and of the four chosen flammable liquids.

The maximum amounts of fuel were applied - 2 1,

3 I resulting into the fires dying out from lack of oxygen.

The waste cotton - 0.1 kg or 0.2 kg

- had in all

cases the shape of a ring.

The results of the most significant tests, - i.e. nos.

E

T

+2000-800 -1000 - 2000-o +1000---20 -19 -18 -17 -16 -15 -10 o o-1+2000_800 -20 -1g - 20--10 o

Fig. 8. Results of Test 17.

L)

E

Fig. 9. Results of Test 23. Iroof Tf ire Fressure Trost ire Pressure Time (minutes) Time (rriiriutes)

12 +2003--800 +1000-0 19 18 17 -1000---16

is

- 2000--10 o

Fig. 10. Results of Test 24.

+2000-800 + 1000 20 1g 18 17 -1000 16 15 6 02 Troof 'fire Pressure -J-Time (minutes) -2000 Iroof 10 Tfire Pressure

Fig. Il Results of Test 25.

Time (minutes)

17, 23, 24, 25 - are shown in Figures 87. 11. It was

found that nearly all the processes of combustion were rather fast.

The maximum pressure rises and drops augmented

with the increase of the burning surface. When the

oxygen contents decreased to 15-16%, combustion stopped suddenly and completely.

Series 2c, Tests 26 and 27

After ignition, the combustion process in Test 26 was rather slow, but that of Test 27 proceeded as seen in

Tests 17 7. 25.

In Test 26, the side-wall was exposed to rather high temperatures for about 20 minutes and so was, in

Test 27, the roof for about 3 minutes.

Construction after the tests

After Tests I to 25, as well as after Tests 26 and 27, the container was carefully inspected.

No damaged parts were found, except sorne discol-ouration occurring here and there on the outer walls and the roof, which resulted from repeated heating.

On the inner surface of the container, a layer of soot, tarry

products, moisture and the

like had deposited.

Soot and the like had also deposited on the outside

of the container, near some small openings in the

walls.

2.2 Measurements of container leakage

2.2.1

Introduction

As described in Report no. 177 M, it can be assumed that the growth o f fire in containers with increasing degrees of ventilation or leakage is as follows:

I. For a container with little or no leakage: a small

fire during a relatively short period of time.

For a container with moderate leakage: a relatively

fierce fire for a relatively long period of time. The

burning rate will decrease with decreasing leakage. For a container with high leakage: a fully developed fire for a relatively short period of time. An in-creasing rate of air supply will cause an increase of

the rate of combustion.

The leakage of the container was now determined in

order to llave a basis for comparison with the

con-tainers tested in ref. [I].

u. L) Deformation of the construction

A rather considerable deformation of the walls and

E

_{the roof was visually observed under the highest}

in-o- _{creasing and decreasing pressures.}

Measurements were carried out immediately before

and after Fire Test i and between Tests 25 and 26. Because the container condition after Test 27,

com-pared with that after Test 25, was apparently similar, a leakage measurement has omitted.

2.2.2

Method used

Air was pumped to or from the empty, well-closed

container by means of an electrically driven reversible ventilator inordertomaintain a pre-determined pressure inside the container. The relation between the quantity

of air to be pumped and the adjusted pressure is re-garded as a measure for the leakage or ventilation of the container concerned. Between the ventilator and the air flow meter, as well as between the flow meter

and the container to be tested, a flexible 130 mm wide tube was fitted.

For connecting the flexible tube to the container, an opening of 130 mm bore was made in a side-wall. For mounting a pressure gauge, a second opening, of

10 mm bore, was made about 2.5 m away from the first opening. The pressure gauge used was a micro-manometer filled with a special type of oil.

Positive and negative pressures of 200 Pa, 500 Pa

and 1000 Pa, respectively, were maintained during the

measurements. The limit of 1000 Pa had been chosen because this value was recorded during the fire tests with the plywood and the steel containers. Moreover

the maximum capacity of the ventilator available during the time of investigation was only a little more

than 1000 Pa difference in pressure.

By a positive pressure is understood: a pressure

above the atmospheric pressure, and a negative

pres-sure means: a prespres-sure below atmospheric prespres-sure. During the fire tests, the apparatus for leakage mea-surements was disconnected and the opening of 130 mm bore in the container-wall provided with a pane of

mica.

Table 111. Results of leakage measurements.

before Fire Test I after Fire Test I

between Fire Tests 25 and 26

leakage in m3/sec x [Ø_3

/

/

/

/

- rcsIT;vE FRESSURE = NEGATIVE FRESSURE /3 I I I 200 '.00 600 800 1000 PRESSURE IN Pa

Fig. 12. Results of leakage measurements. For comparison are also given, the results of steel and plywood containers (1) with highest and lowest leakage.

2.2.3

Results

The results are summarized in Table Ill. For

compar-ison, some results are also given that relate to the plywood and the steel containers of ref. [I].

For easy reference, the results are also presented in Figure 12; it plots the adjusted pressures, both

posi-tive and negaposi-tive, in the same direction along the X-axis and the quantities of air along the Y-axis.

3 Discussion of results

3.1 Fire tests

3.1.1

Fuel used: wood cribs (Part I)

The processes were in general similar to those as ob-served in the plywood and steel containers; the

dura-tion of an average process was half an hour.

The decrease of the oxygen contents to a minimum

of 91 1 as well as the consumed quantities of wood (5-8 kg) confirm that the investigated container may

be considered as one to have little leakage.

If more or less ignition liquid drips on the floor near

or under the crib, and flows into the seams, a fire can start in these places. As shown in Tests I and 4, pene-tration of fire will occur: this involves much risk for the container and its surroundings.

200Pa 500Pa l000Pa

pos neg pos neg Pos neg

108 113 78 185 260 270 58 57 96 95 140 140 40 39 74 65 120 96 3 3 6 6 II 9 80 86 147 152 230 240 72 66 113 III 196 195 51 49 89 84 135 26 260 E o 4 4 ¶ 195 130 65 serial

number container type

3 steel with 11 J ventilation Jplywood 121) 13 ) aluminium 14 )

14

3.1.2

Fuel used: flammable liquids

(Part II, Series I)

As demonstrated in Test 7, a burning liquid on the

floor as constructed in the container under test is

very dangerous.

Within some minutes after ignition, flames pierced through the seams in the floor after which the floor caught fire.

Series II, part 2

Observation of the burning processes of liquids ap-plied in steel trays showed that, in general, these pro

cesses were violent but had a short duration.

The violence of the fire could be judged from the

rapid pressure alternations, and from the extreme values of the pressure.

The violence of the tire depended on the burning surface, too. See the results obtained with tray 21 B

(Tests i7, 25, 24 and 23) compared with those obtained with tray 8B (Tests 18, 20, 21 and 22).

No significant relation was found between the

violence of the fire and the flash point of the liquids

used, as can be seen in Table IV.

The table also shows the maximum amounts of fuel consumed in the closed container.

Table IV. Comparison between violence of the fire and flash point of the used liquids.

The processes in tray 8B stopped suddenly, and

com-pletely, after 4-7 minutes and in tray 21B after 2-4

minutes; except that of ethylene glycol, which always took some minutes more.

The oxygen contents decreased to 15-16%. Some minutes thereafter, when the pressure in the container

had reached the level of that outside the container, the oxygen contents were increased with about 1%.

A normal process had taken place within lO minutes.

The construction, subjected to intense heating as in

Test 2(23 kg of wood in a corner), Test 26(2 1 kerosine

in tray along a wall) and Test 27 (2 1 kerosine in tray closer to the roof), had fully resisted that heating: it

remained intact.

3.2 Container leakage

The leakage of the container before the test series was

similar to that of the steel container with the highest

rate of leakage.

lt may thus be stated that the fire tests have been

carried out in a aluminium container having little leakage [I].

4 Conclusions 4.1 Leakage

Although the aluminium container had some damage,

the rate of leakage did not exceed the measured

leakages of the ventilated steel containers.

After the fire tests, the rate of leakage had decreased

some 40%. This must be caused by soot and the like,

which had deposited in seams and other small openings in the construction.

4.2 Aluminium construction

The construction fully resisted the wood-fires and the fires of the chosen liquids, even when the walls and

roof were exposed to intensive heating.

They did not melt, as had been tentatively supposed.

4.3 Floor

In view of fire the construction of the floor did not

meet the requirements of fire safety.

Both with leaked methylalcohol, in the tests with

wood as a fuel, and with kerosine poured on the floor,

fire penetrated in

a very short time after ignition

through seams in the floor.

Moreover the wooden floor caught fire thus

pro-moting spread of fire.

A fully closed floor, as for instance that used in

plywood containers, will give more safety and will

prevent penetration of fire fairly well.

4.4 Fuel

The combustion of the applied liquids appeared violent

compared with that of the ordinary combustible wood; on the other hand, the processes had a very

short duration.

4.5 Risk

[f subjected to an internal tire of a liquid having a

flash point sufficiently high above the ambient tem-perature, the aluminium container may be considered as being safe; on the understanding that the construc-tion of the floor prevents penetraconstruc-tion of fire, and the leakage or ventilation is little, in these cases, the risk

maximum flash

maximum pressure rise (Pa)

tray tray

consump- point

tion (I) liquid OC 8B test 21B test

ca. 1 kerosine 50 1400 18 2450 17

ca. 2 ethylene glycol 40 500 20 2150 25

ca. 2 butanol 35 900 21 3200 24

for the ship. if a leaked liquid catches fire, may be re-garded to be low compared with similar situations on

conventional dry-cargo ships.

After all, this conclusion may be also related to the

containers of plywood and steel under the same

conditions.

Besides, the conclusions regarding plywood and steel containers, if inside these containers occur fires of

or-dinary combustibles like wood, paper, etc. as

men-tioned in Report no. 177 M, may be related in the same way to the aluminium container.

5 Suggestions for future work

I. _{Tests in containers having a leakage of more than} 420 m3/sec x iO at 1000 Pa overpressure, as sug-gested in Report no. ¡77 M. have not yet been carried out.

The behaviour of containers, when exposed to an external fire may be of interest, especially when it

concerns a fire of a burning liquid.

The fire resistance of several types of containers

subjected to external fires should, therefore, be determined.

The phenomenon of self-heating and self-ignition of some commodities in containers is another im-portant aspect.

As is mentioned in Report no. 177 M, tests with

this kind of cargo are either difficult, or impossible,

because of the dangerous character of the

experi-ments involved.

6 AcknowLedgements

The Netherlands Ship Research Centre TNO

acknowl-edges the cooperation of the Koninklijke Nedlloyd B.V., the Koninklijke Nederlandse Redersvereniging

and the Scheepvaart Inspectie, which made possible the carrying out of the work reported above.

References

1. SOUER. Ing. H. J., Maritime transportation of containerized cargo. Part lit. Fire tests in closed containers, Apri! 1973. Netherlands Ship Research Centre TNO, Report No. 177 M.

ELTEREN, dr. J. F. VAN and H. J. S0UER, Onderzoek aan een

container, Rapport No. BV-72-60 Technical Centre for Fire Prevention TNO; August 1972 (not published).

ELTEREN, dr. J. F. VAN and H. J. SOUER, Onderzoek aan

con-tainers. Rapport No. BV-72-80 Technical Centre for Fire

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brand-proeven in gesloteri containers. Rapport No. BV-74-22

Tech-nical Centre for Fire Prevention TNO; May 1974 (not

PUBLICATIONS OF THE NETHERLANDS SHIP RESEARCH CENTRE TNO LiST OF EARLIER PUBLICATIONS AVAILABLE ON REQUEST

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Reports

I 14 5 The steering of a ship during the stopping manoeuvre. J. P. Hooft. 1969.

115 s Cylinder motions in beam waves. J. H. Vugts, 1968.

1 16 M Torsional-axial vibrations of a ship's propulsion system. Part I. Comparative investigation ofcalculated and measured

torsional-axial vibrations in the shafting of a dry cargo motorship.

C. A. M. van der Linden, H. H. 't Hart and E. R. Dolfin. 1968. 117 S A comparative study on four different passive roll damping

tanks. Part II. J. H. Vugts, 1969.

I 18 M Stern gear arrangement and electric power generation in ships propelled by controllable pitch propellers. C. Kapsenberg. 1968. I 19 Nl Marine diesel engine exhaust noise. Part IV. Transferdamping data of 40 modelvariants of a compound resonator silencer. J. Buiten, M. J. A. M. de Regt and W. P. Hanen, 1968. 120 C Durabilitytestswithprefabrication primers in usefor steel plates.

A. M. van Londen and W. Mulder, 1970.

121 5 Proposal for the testing of weld metal from the viewpoint of brittle fracture initiation. W. P. van den Blink and J. J. W. Nib-bering, 1968.

122 M The corrosion behaviour of cunifer 10 alloys in seawaterpiping-systems on board ship. Part I. W. J. J. Goetzce and F. J. Kievits,

1968.

123 M Marine refrigeration engineering. Part III. Proposal for a specifi-cation of a marine refrigerating unit and test procedures. J. A. Knobbout and R. W. J. Kouffeld, 1968.

124 S The design of U-tanks for roll damping of ships. J. D. van den Bunt, 1969.

125 S A proposal on noise criteria for sea-going ships. J. Buiten, 1969. 126 S A proposal for standardized measurements and annoyance rating of simultaneous noise and vibration in ships. J. H. Janssen, 1969. 127 S The braking of large vessels II. H. E. Jaeger in collaboration with

M. Jourdain, 1969.

128 M Guide for the calculation of heating capacity and heating coils for double bottom fuel oil tanks in dry cargo ships. D. J. van der 1-leeden. 1969.

129 M Residual fuel treatment on board ship. Part III. A. de Mooy, P. J. Brandenburg and G. G. van der Meulen, 1969.

130 M Marine diesel engine exhaust noise. Part V. Investigation of a double resonatorsilencer. J. Buiten, 1969.

131 S Model and full scale motions of a twin-hull vessel. M. F. van Sluijs, 1969.

132 M Torsional-axial vibrations of a ship's propulsion system. Part II. W. van Gent and S. Hylarides, 1969.

133 S A model study on the noise reduction effect of damping layers aboard ships. F. H. van ToI. 1970.

134 M The corrosion behaviour of cunifer-lO alloys in seawaterpiping-systems on board ship. Part II. P. J. Berg and R. G. de Lange,

1969.

135 S Boundary layer control on a ship's rudder. J. H. G. Verhagen,

1970.

136 5 Observations on waves and ship's behaviour made on board of Dutch ships. M. F. van Sluíjs and J. J. Stijnman, 1971. 137 M Torsional-axial vibrations of a ship's propulsion system. Part iII.

C. A. M. van der Linden. 1969.

138 S The manoeuvrability of ships at low speed. J. P. Hooft and M. W. C. Oosterveld, 1970.

139 S Prevention of noise and vibration annoyance aboard a sea-going passenger and carferry equipped with diesel engines. Part I.

Line of thoughts and predictions. J. Buiten, J. H. Janssen,

H. F. Steenhoek and L. A. S. Hageman, 1971.

140 S Prevention of noise and vibration annoyance aboard a sea-going passenger and carferry equipped with diesel engines. Part II. Measures applied and comparison of computed values with measurements. J. Buiten, 1971.

141 S Resistance and propulsion of a high-speed single-screw cargo liner design. J. J. Muntjewerf, 1970.

142 S Optimal meteorological ship routeing. C. de Wit, 1970. 143 S Hull vibrations of the cargo-liner "Koudekerk". H. H. 't Hart,

1970.

144 S Critical consideration of present hull vibration analysis. S. Hyla-rides. 1970.

145 S Computation of the hydrodynamic coefficients of oscillating cylinders. B. de Jong, 1973.

146 M Marine refrigeration engineering. Part IV. A Comparative stuyd on single and two stage compression. A. H. van der Tak, 1970. 147 M Fire detection in machinery spaces. P. J. Brandenburg. 1971. 148 S A reduced method for the calculation of the shear stiffness of a

ship hull. W. van Horssen, 1971.

149 M Maritime transportation of containerized cargo. Part II. Experi-mental investigation concerning the carriage of green coffee from Colombia to Europe in sealed containers. J. A. Knobbout. 1971. 150 S The hydrodynamic forces and ship motions in oblique waves.

J. H. Vugts, 1971.

151 M Maritime transportation of containerized cargo. Part I. Theoretical and experimental evaluation of the condensation risk when transporting containers loaded with tins in cardboard boxes. J. A. Knobbout, 1971.

152 S Acoustical investigations of asphaltic floating floors applied on a steel deck. J. Buiten, 1971.

I 53 S Ship vibration analysis by finite element technique. Part II. Vibra-tion analysis. S. Hylarides, 1971.

1 54 5 Canceled.

155 M Marine diesel engine exhaust noise. Part VI. Model experiments on the influence of the shape of funnel and superstructure on the radiated exhaust sound. J. Buiten and M. J. A. M. de Regt, 1971. 156 S The behaviour of a five-column floating drilling unit in waves.

J. P. Hooft, 1971.

157 S Computer programs for the design and analysis of general cargo ships. J. Holtrop. 1971.

158 S Prediction of ship manoeuvrability. G. van Leeuwen and

J. M. J. Journée, 1972.

159 5 DASH computer program for Dynamic Analysis of Ship Hulls. S. Hylarides, 1971.

160 M Marine refrigeration engineering, Part VII. Predicting the con-trol properties of water valves in marine refrigerating installations A. H. van der Tak, 1971.

161 5 Full-scale measurements of stresses in the bulkcarrier m.v. 'Ossendrecht'. ist Progress Report: General introduction and information. Verification of the gaussian law for stress-response to waves. F. X. P. Soejadi, 1971.

162 S Motions and mooring forces of twin-hulled ship configurations. M. F. van Sluijs. 1971.

163 S Performance and propeller load fluctuations of a ship in waves. M. F. van Sluijs. 1972.

164 S The efficiency of rope sheaves. F. L. Noordegraaf and C. Spaans,

1972.

165 S Stress-analysis of a plane bulkhead subjected to a lateral load. P. Meijers, 1972.

166 M Contrarotating propeller propulsion, Part I, Stern gear, line shaft system and engine room arrangement for driving contra-rotating propellers. A. de Vos, 1972.

167 M Contrarotating propeller propulsion. Part II. Theory of the dynamic behaviour of a line shaft system for driving contra-rotating propellers. A. W. van Beek, 1972.

169 S Analysis of the resistance increase in waves of a fast cargo ship. J. Gerritsma and W. Beukelman, 1972.

170 S Simulation of the steering- and manoeuvring characteristics of a second generation container ship. G. M. A. Brummer, C. B. van de Voorde, W. R. van Wijk and C. C. Glansdorp, 1972. 172 M Reliability analysis of piston rings of slow speed two-stroke

marine diesel engines from field data. P. J. Brandenburg, 1972. 173 S Wave load measurements on a model of a large container ship.

Tan Seng Gie, 1972.

174 M Guide for the calculation of heating capacity for deep tanks. D. J. van der Heeden and A. D. 175 S Some aspects of ship motions in irregular bea

waves. B. de Jong. 1973.

176 5 Bow flare induced springing. F. F. van Gunste 177 M Maritime transportation of containerized carg

tests in closed containers. H. J. Souer, 1973. 178 S Fracture mechanics and fracture control for shi

J. J. W. Nibbering, 1973.

md heating coils Koppenol, 1972. m and following ren, 1973.

o. Part III. Fire