PROPOSED CEN STANDARD IN COMPARISON WITH ISO FOR THE ASSESSMENT OF THE FIRE BEHAVIOUR OF MASONRY

Chrístiane Hahn 1 ABSTRACT

Up to now the assessment of fire behaviour of masonry walls is done according to national standards or even only to national judgement. Because of the attempt to open the European market the work on harmonising the standards started . This paper presents the work for the assessment of fire behaviour of masonry that is presently done in the CEN committies CEN/TC 127 "Fire Resistance Testing of Building Elements", CEN/TC 250 SC 6 PT 7 "Structural Fire Design for Masonry" and also explains the concept that is wrítten down in the "Interpretative Document" .Finally a comparison with ISO will dose this subject.

2 INTRODUCTION

To get the European market started harmonised standards are necessary. For realizing the decisions for harmonisation the European standard organisation CEN was asked by the European commission to set up harmonised standards. For the work technical commities with working groups (WG) and task groups (TG) were founded.

For the dead line 31.12 .1993 the complet standards should be finished. The work for the international standards (ISO) is still done parallel in some cases. But mainly the work is done according to the Vienna agreement.

New european standards shall be set up and shall replace the national standards after a certain transitional períod o

Keywords: Masonry ; Fire Assessment; CEN Standards; European Market.

Dip!.-Ing., Deputy head of the fire department Institute for Building Materials , Solid Construction and Fire Protection Technical University Braunschweig Germany Te!. int+531-391-5465

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Institut für Baustoffe, Massibau und Brandschutz Beethovenstr. 52 D - 38106 Braunschweig Fax int+531-391-4573

3 BLANKET CLAUSE FOR FlRE PROTECTION

3.1 Construction Product Directive

The European commission set the blanket clause for fire protection in the "Construction Product Directive" as follows:

"The construction works must be designed and built in such a way that in the event of an outbreak of fire :

the loadbearing capacity of the construction can be assummed for a specific period of time, the generation and spread of fire and smoke within the works are limited, the spread of the fire to neighbouring construction works is limited, occupants can leave the works or be rescued by other means, the safety of the rescue teams is taken into consideration."

The requirements itself which are necessary to fulfill this blanket clause are defined in the "Interpretative Document for the Essential Requirement - Safety in Case of Fire" (Last version complete, July 1993).

3.2 Interpretative Document

The general requirements, the concept and the basis for fire protection are described. It is differentiated between loadbearing and non-loadbearing building elements with separating or non-separating function . Therefore wall typs are defined

The criteria for the evaluation of the building components are as follow :

R : Loadbearing criterion Structures shall maintain their loadbearing function during the relevant fire exposure

E : Integrity criterion Defines the ability of a separating member (wall) to prevent passage of flames and hot gases during the relevant fire exposure

I : Thermal insulation Defines the ability of a separating member (wall) to prevent excessive transmission of heat during the relcvant fire exposure

W : Radiation criterion Defines the insulation of a separating member on the basis of the radiation emitted during the relavant fire exposure

M : Mechanical criterion Structures shall maintain their loadbearing capacity and their integrity under mechanical impact during the relevant fire exposure

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4 CEN/TC 127

4.1 General

CEN/TC 127 works on the assessment of fire behaviour. CEN/TC 127 started working in 1991 and set up a very tight time table for producing the standards for the buiIding elements. Nearly alI standards were supposed to be ready for stage 41 - public presen­tation for the 6 manth inquiry - at the end af 1992, but there is a deIay. Provisonal mandates were handed out mainIy to ad hoc groups. Additionally, work was given to EGOLF - European Group of Laboratories for Fire - to reach the above mentianed aim.

CENITC 127 Fire safety in buildings

Working groups Arbeits-Gruppen

WG1 WG 2 l sd hoc group 1

J Non-combustibility

European reaction of INichtbrennbarkeit)

Harmonized test preparation and fire classification

~ sd hoc group 2

J translation of national Ignitability

classifications (Europãische (Endzündberkeitl

Klassifizierung des

I sd hoc group 3

J I Probenvorbereitungen Brandverhaltens von Flcor coverings und Übertragung von Baustoffen) IBodenbelãgel nationalen Klassifi· zierungen)

I sd hoc group 4

J Roof tests (Bedachungenl

I ad hoc gtOUP 5

J Door and shutter assemblies (Feuerschutzabschlüsse)

I sd hoc group 6

J Penetration seals (Abschottungen)

I sd hoc grcup 7

J Strategy (Str8tegieJ

I ed hoc group 8

J Smoke IRauch)

I sd hoc group 9

J Partitions (Trennwãndel

l ed hoc group 10

I Additional requirements (zus ãtzliche Anforderungen)

~ ed hoc group 11

I Damper. ventilation ducts ILüftungsleitungen)

Figure 1: Overview CEN/TC 127

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4.2 CEN standardisation for masonry

Ad hoc group 9 "Partition" set up the standard for testing alI types of walIs including masonry. This group started onIy on non-Ioadbearing internai walIs with separating function. Additional tasks are non-Ioadbearing externai walIs with or without separating function, Ioadbearing internai and externai walIs, both with or without separating function, and facades now . Masonry is used for alI of these types .

"> 100 > 100 "> 100

~,--_----"I -~-",4'f.-""-"---=:----'-<:L~r~1=f--j tragende Lr ,/ raumabschlieBende direction of floor span AuBenwande •

Balken (Stürze)

tragende, nicht· raumabschlieBende AuBenwande

Stützen (Mauerwerkspfeiler)

tragende, nicht· raumabschlieBende Innenwande

! Deckenspannrichtung

direction of flol~or~s~p~a~n ---:E~::::::=== nichttragende Trennwânde

tragende, raumabschlieBende Innenwand

loadbearing, separating inside wall

Figure 2: WalI types (exampIe)

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loadbearing separating outside walls

lintels

loadbearing non·separating outside walls

columns

loadbearing non-separating inside walls

non·loadbearing partitions

For alI of these wall types single papers wiU be set up as folJow :

EN YYY 1 General requirements for - Part 1: General testing and Fire Resistance Testing performance require-

ments

EN YYY 2 Fire Resistance Testing - Part 1: Partitions of Nonloadbearing Elements - Part 2a: External walls

- Part 2b: Facades

EN YYY 3 Fire Resistance Testing - Part 1: Internal walls of Loadbearing Elements - Part 2: External walls

EN YYY 5 Contribution to Fire Resist- - Part 6: Applied protection ance of Structural Members to masonry eJements

EN QQQ 1 Material Properties at - Part 1: General requirement High Temperatures - Part 4: Masonry

CEN/TC 127 defines the basis for fire protection and sets up the testing standard for the assessment. Depending on the building element the test methodes are defined very detailed . For example the loading system or the mechanical impact are defined exactly.

Furnace

Hydraulic ---+\ Jacks

Figure 3: Loading system

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Sectional Elevation

.t-. 8renner

J 1500~

Figure 4: Mechanical impact

\ Release Equipment

. ~aCkle .'-......- -l";ll ....... ::..--.. . . ~ ~

. ~,.\ \~, -1'

I o '<:~../ . 8 25

,I, gj~ l l~L M z~· . Komplextrennwand

1.000Nm Brandwand 3000 Nm

"'-. 200 kg Lead Shot

O.K.F. Halle

Hydraulic Jacks

The background for these precize definitions is that test results alI over Europe will be accepted . Up to now clients have to test in each European country, if they need the assessments because test results achieved in other countries will not be accepted.

The intemational standardization (ISO) onIy describes the general concept up to now , Details are not given.

Within EGOLF - European Group of Laboratories for Fire - there was a group working on protection of masonry -cladding, pIaster, etc ,

5 CEN/TC 250 SC 6

5.1 General

CEN/TC 250 SC 6 PT 7 works on the "Structural Fire Design of Masonry" . The revised version of EC 6 part 10 wiU be presented in June 1994. The basis for this paper is Eurocode 6 part 10 [1].

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Figure 5: Overview CEN/TC 250

5.2 CEN/TC 250 SC 6 PT 7

PT 7 StNctuta' Fire Quion

This paper defines the possibilities to assess the fire behaviour of masonry. On principie there will be 3 equal ways as follow:

- Testing the masonry wall according to CEN/TC 127 - Assessment according to tabulated data - Assessment by calculation

* simplified calculation method * general calculation method

The revised version wiU only present tabulated data for the assessment of fire behaviour of masonry. Tables for each wall type will be set up although it is rather difficult to mix test results from different countries with different types of units and loading.

Contrary to alI other building materials , i .e. concrete, there exists no calculation method for assessing the fire behaviour of masonry up to now. Further details to the paper will be given at the presentation because at that time a redrafted version will exist.

6SUMMARY

The general blanket for fire protection according to the "Construction Product Directive" and the "Interpretative Document" for the harmonized European market is presented . The testing methods for the assessement of fire resistance for masonry are drafted in CEN/TC 127. Essential requirements are summarized . The work is very

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detailed in contrast to the ISO-work.

CEN/TC 250 SC 6 PT 7 is presented. It is necessary to start a European discussion to be able to finalize this paper during the 3 year testing period. Up to now it is rather unsatisfactory .

REFERENCES:

[1] Haseltine, B. , Hahn, Chr., Waldum, Alf: Eurocode 6, part 10: "Structural Fire Design for Masonry", Draft 1993

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