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Technical Note (National Research Council of Canada. Division of Building Research), 1970-03-01
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Meeting of IMCO Subcommittee on Fire Protection, London, 1-5 Dec.
1969
Williams-Leir, G.
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,
NATIONAL RESEARCH COUNCIL OF CANADA
OF BUILDING RESEARCH DIVISION
'fE
C
1HI N ][ CAlL
NOTlE
No.
546
PREPARED BY G. Williams -Leir CHECKED BY G. W.
s.
APPROVED BY A. G. W. DATE March 1970 PREPARED FOR Record PurposesSUBJECT MEETING OF !MCO SUBCOMMITTEE ON FIRE PROT ECTION, LONDON. 1-5 DEC. 1969.
For this meeting the Ad Hoc Group on Fire Test Procedures reverted to its usual procedure of meeting, without simultaneous
translation facilities, on the Monday preceding a Subcommittee meeting. Denmark has now had time to complete the analysis of the
cooperative program on combustibility of glass wool and rock wool; Mr. Malmstedt introduced a report that tabulates each measurement from each country. The conclusion drawn is that all rock wools and most glass wools currently in use in ship construction would be classi-fied as combustible by the ISO test as it now stands.
He considered, and the Group seemed to agree, that such m.aterials were not a serious fire hazard, and suggested that the test method should be am.ended to accept them. In a discussion between Robertson and Malhotra it became apparent that inserting the specimen holder and a totally inert specimen raises the temperature by 35 to 40° C, due not to com.bustion but to altered paths of air convection. The com-bustible content needed to raise the specimen a further 15 degrees and thus fail it may be very small indeed. Malmstedt proposed that temper-ature rise be measured from the level to which it falls after the combus-tible content of a specimen is consumed, and that a maximum rise of 75° C
,.
2
-above this level be taken as the criterion of combustibility. He sub-rn.itted a draft test specification (FP IX/2(c) Add. 1) along these lines
entitled "Non-corn.bustibility Tests on Fibrous Materials." One merit of this test was that its results were consistent with those of the U. S. "hot rivet" test. McDaniel objected to the idea of having different tests for different categories of rn.aterials; this would mean that the
definition of 'fibrous' rn.ight be critical in deciding whether a rn.aterial was combustible or not. It was generally agreed that we did not want to be in the position of having to do prelirn.inary tests to determine which combustibility test was applicable.
In com.paring the arrangement of the therrn.ocouples in FP IX/2 (c) Add. 1 with that proposed by Denmark in FP VIII/6 (February 1968) for the cooperative exercise, their num.ber is reduced from six to four by omitting the one at the centre of the specimen and the one above it, and re-spacing the other four at 90° intervals around the specimen.
Dr. Biase of Italy suggested an alternative method of reducing the severity of the ISO test. Instead of considering the worst of three specimens tested the rn.ean should be taken, after rejecting aberrant readings, by the use of Chauvenet's criterion.
This subject is further developed in the Italian paper
FP IX/2 (c)/l of 1 Decern.ber 1969, which also suggests the abandon-m.ent of visual observation for "£larn.ing." Bellison of France expressed approval of the U. S. "hot rivet" test.
Robertson (U. S.) described discussions with industry of the ISO test. There were a number of objections to it: the length/diarn.eter ratio was less than in the ASTM furnace, resulting in less uniform temper-ature in the working area; the density of the refractory tube, specified as 1. 5 to 2, would be better in the range of 2 to 3; and, details of construction, heater winding and insulation, were inadequately specified. It was also thought that it would be an improvern.ent to insulate the diffusion cone through which air enters the furnace and thus increase the preheating of the air flow. An optical pyrometer had shown that the specification could be met under these conditions with the furnace wall at 790°C, when other-wise 835° C was necessary.
Malrn.stedt said that thes e points had all been consider ed. The correlation between the results obtained by eight laboratories in the comparative exercise is much improved if, as proposed by Denrn.ark, temperature rise is calculated from the final steady furnace temperature rather than as in the present ISO specification. If this procedure were adopted, therefore, Robertson's points would cease to be as important.
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-Robertson agreed, but pointed out that the Danish procedure would be costly in terms of laboratory time needed to perform the test; e. g. one hour instead of 20 minutes. Malmstedt said 20 minutes was enough for fibrous materials but other materials would take longer.
The Chairman suggested deleting the restriction 'for fibrous materials' wherever it occurred in the Danish draft. Unfortunately no time remained to complete a specification.
The discussion on the Deck Coverings test was somewhat disconnected. Since the phrase 'will not readily ignite' was used in
the 1960 convention, such drastic changes have been made in the require-ments for decks themselves that it is even in question whether there is any need for the kind of test discussed in previous meetings.
(1) Decks are now supposed to be so insulated in relation to the fire load of the compartments separated that, if the system achieves its aim, fire should never be started by conduction through decks. (2) Because some thin coating, perhaps just paint, will have to be applied even if it fails the test, a lower limit of three mm has been set, below which thickness coverings are exempt; this exemption includes some of the more severe hazards.
(3) Ifthis test were abandoned (and there is no immediate prospect of this) there would still be some simpler test necessary, such as the pill test used for carpets, to eliminate flam.mable floors that would ignite from heat from above.
(4) The term 'primary deck covering' has not been defined to common satisfaction. Most agree to exempt carpets, many would exempt floor tiles and linoleum, etc., some would test only the lowest layer in direct contact with the steel.
During a recess the author discussed DBR's smoke measurements on the IMCa flame spread specimens with Robertson who agreed to arrange for testing a set; the materials were to be supplied from offcuts still held by DBR.
The meeting then continued to the third and final main topic, flame spread. Seven countries had recently taken part in a comparative exercise, each using its own test on the same six materials. Results were compared, and each delegation stated which of the six materials would be acceptable to its administration.
4
-It was necessary to explain an anomaly in the Canadian results. The exercise was a continuation of one for which arrangements had been made at the February 1968 meeting; ASTM E-162 test was chosen to be used. Since then. Marine Regulations Branch has issued "Fire Test Procedures for Materials" in which ASTM E-84 is the criterion for flame spread. The levels of acceptance set are identical with those adopted by the U. S. Coast Guard. On the basis of the results presented by the U. S. delegation. therefor e, it was possible to state that Canada would accept only material No.6. epoxy paint, on steel. The anomaly lay in the
fact that this was not the material with the best performance in the E-162 test. Four other countries. Denmark. France. Italy and United Kingdom, would all accept materials Nos. 2, 5 and 6, some with qualifications. while Germany would accept them all.
There was some dissatisfaction expressed with the numerical agreement between the different tests as presented in a diagram prepared by Malhotra. The author said that the correlation on a rank basis appeared not too bad, and that if the U. S. would raise its acceptance level somewhat. say from 20 to 35, there would be substantial agreement between most countries.
Robertson pointed out that all six materials were chosen as potentially satisfactory materials for situations where the Convention calls for flow flame spread'; if some more flammable materials had been included the international correlation would probably appear better.
One observation put on record here is that the flash flaming index on E-162 correlates noticeably better than the sustained flaming index with the tests used by other countries.
The Chairman concluded by saying that although the Ad Hoc Group had done a good job, it should not go into competition with ISO in this
field of study. It should report to the Subcommittee and leave the question of further work to them.
The Group then passed on to the amendment of the specification for fire tests on A and B class partitions. It had been agreed at the June 1969 meeting that an error in the description of the asbestos pads for the unexposed surface thermocouples should be corrected. The U. S. delegation now proposed that the new values agreed upon for density and thermal conductivity should each be associated with a tolerance of ±10 per cent. This was promptly agreed to, and after some discussion on procedure for the rest of the week. the meeting adjourned.
/
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5
-On 2 December the full Subcommittee met with 74 members representing 18 countries and 8 international organizations. There was some commotion in the Canadian delegation when a message was received instructing it to withdraw the report on Canada1s share in
the cooperative exercise on flam.e spread. as it had not yet received authority from the Department of Transport.
The meeting was opened by Sasamura. who after welcoming new delegates. including one from Liberia. called for nominations for chairman. Hareide of Norway was nominated by McDanieL
unopposed. and was elected. with Fribert of Denmark as Vice-Chairman. The agenda was discussed and it was recommended that
priority be given to Items 2, 3 and 5: fire tests. tankers. and cargo containers. The Ad Hoc Group on Fire Tests would go into separate session and its report would be required the morning of 4 December 1969. Malhotra then presented an interim account of the Monday
proceedings. There was discussion of the U. S. report on Deck Coverings FP IX/2( a). Italy proposed a surface spread of flame test should be used to qualify deck coverings. AU. K. delegate said some solution was needed soon. Malhotra summed up the discussion by saying that the Subcommittee was asking the Group for "something simple. "
The Group members left and met in Room 310. They started with the document" Provisional Guidelines on Test Procedures for Deck Coverings." It was pointed out by a Danish delegate that the general idea
of the present test was introduced at a time when any deck in a ship was of AO construction. Now that. since the 1966 amendments. every deck of a ship was supposed to be insulated in relation to the fire hazard of the spaces separated, deck coverings should not be exposed to such severe fires as before.
There was a discussion on effect of thickness. It was agreed that. other things being equal, a thin layer would ignite before a thick one. This produced an anomalous situation; a 6 -mm layer of a material might ignite at 14 min and fail. while a 3 -mm layer of the same material that ignites at 7 min would be exempt. To some delegates this mean the limit for exemption should be lowered. to others it meant it should be raised.
The logic of the pilot flame was similarly questioned. Should one not rather test for the spontaneous ignition point. especially as no valid smoke measurements can be taken after pilot ignition? Dr. Biase suggested three tests each way. dispensing with the smoke canopy when one is going to use the pilot flame.
/ 6
-The author suggested that the number of tests necessary could be halved if one measured sm.oke up to the critical time, 15 min. and then applied the flame. Malmstedt objected to anything that
would render future tests not com.parable with those already done in two international exercises. Bellison suggested two specimens should be subjected to a 15 -min test for ignitability. and one to a 30 -min smoke test. This was agreed to by a m.ajority. and is incorporated in the report.
The Group also agreed on a new thickness for the steel plate, with a toler anc e that permits the us e of 3/16 -in. plates. Dr. Bias e proposed a new arrangement of furnace thermocouples which was adopted. He also suggested spark ignition in place of the pilot flame. The Group's report is phrased to permit this but not to displace flam.e ignition.
Dr. Biase wanted a third test to be done when two disagree, but a majority was content to adopt the worse result of two. Bellison wanted to extend the ignitability test to 20 min. but no one agreed.
There was some concern over whether any of the available m,aterials would attain the standard prescribed in paragraph 14 of the draft for smoke. It was decided to report only ,the times at which optical density passes the 1 and 2 values and not to specify a criterion of acceptance.
On 3 December 1969 we went on to Flame Spread. There was a lengthy discussion on how the results from, seven countries could be reconciled.
The meeting then moved on to the Combustibility Test.
Malhotra was against trying to settle the problem.s in this group when Working Group 2 of ISO/TC 92 was working on it. but Robertson disagreed; ISO was not under the same pressure of ｵｲｧ･ｮｾ practical problem,s as we were; we could not wait for them. Malmstedt and Biase supported Robertson, who went on to propose some detailed modifications to define the ISO combustibility furnace more closely.
Malhotra did not object to the modifications, but thought they should be coordinated with ISO. Malm.stedt's reason for not being content with ISO was that this test rejected fibrous m.aterials - mineral and glass wool - that were well accepted. Robertson agreed that there were materials satisfactory in the U. S. thot rivet' test that would fail the ISO test.
/ 7
-The Group's report is now available. and makes clear their view on the combustibility test procedure proposed by the Danish delegation (FP IX/2(c)/Add. 1 of 24 November 1969).
On 4 December 1969 the report of the Ad Hoc Group was presented by Malhotra. McDaniel. for the U. S., thought the new procedure for deck coverings was a step backward. Be said that nothing less than 10-mm thick should be restricted. -As at prevtous meetings. the definition of 'primary deck covering' was argued about. Italy wanted to test only the first material applied to the steel, if over 5-mm thick. U. S. S. R. wanted to ｴ･ｾｴ all the layers. including lino or tiles. below that on which one walks, the latter being qualified by another test.
The author proposed a definition that was unambiguous and which provided a compromise between the ･ｾｲ･ｭ･ｳＮ "Primary deck coverings should include everything applied as a liquid or powder or mixtures of these, and exclude everything in the form of a roll, sheet. or tile. Adhesives used to fix the latter materials are also excluded." The argum,ent continued. Eventually an Italian proposal was adopted by a majority and. on the suggestion of the, U. S., was passed on to a group consisting of U. S. S. R .• Spain. U. S. A. and Italy for drafting.
The meeting then considered the report of the Ad Hoc Group on Fire Safety MeasureS for Tankers. It returned to the paragraph by paragraph examination of the Fire Test Procedures report. Some details were discussed. but it was clear that the preparation of the annexes on Fire Test Procedures to the report of the Subcomm,ittee would have to be prepared by the Secretariat, assisted by Robertson.
This completed the part of the meeting with which the author was concerned.
In commenting on the meeting as a whole, it seems that as time passes, and as the item,s on which agreement could be reached
quickly or in the course of a few meetings are eliminated from the agenda. and as the Subcommittee grows more unwieldy. progress seems relatively slower. Six of the countries would have assisted progress by not sending delegations as they had nothing to contribute. Simultaneous meetings of the 'Group and the Subcommittee have the advantage that the, ｬ｡ｾＬｯｲ｡ｴｯｲｹ people are left alone together and only technical questions are discussed; this tends to assist agreein ent. The administration representatives, however. have the authority and are influenced by considerations of national interest. so there is a tendency to reopeIl, at Subcommittee 'level, questions on which the Group have reached agreement. Progress is also hampered by undue reverence for expressions that were perhaps put in the Convention in 1960 without their meaning having been fully thought out.
