LPS 1158: Issue 2.2 Requirements and tests for fire resistant glazing systems
This Standard details the technical requirements for the certification of fire resisting glazing. It is applicable to the certification of:-
o specific glasses for use in a range of described proprietary and/or generic framing systems;
o specific framing systems for use with a described range of glasses; and
o specific glazing materials for use with described framing systems and glasses.
It is applicable to both insulating and non-insulating glass/glazing systems having fire resistances of 30, 60, 90 and 120 minutes as defined in BS 476 : Part 20 in either horizontal and/or vertical orientations.
This Standard covers the use of glass in fire resisting door assemblies but is not applicable to the door assemblies themselves, which are the subject of other schedules
requirements.
Certification of products will be issued on the basis of initial type tests followed by regular audit tests. It is also required that products be manufactured under a quality management system in accordance with ISO 9001. Details of these requirements and the general rules governing the certification are published separately.
Products will be certificated for specified end use conditions including size and configuration. The scope of certification will be determined by assessment of the fire test information in accordance with the methodology given herein.
NON-FIRE REQUIREMENTS
Glasses shall be classified in accordance with the requirements of BS 6206. This shall be reported in the certification issued. Although not directly affecting fire performance such information may be useful in establishing compliance with the requirements of Part N of Schedule 1 to the Building Regulations regarding glazing – materials and protection.
FIRE REQUIREMENTS
Fire testing shall be conducted in accordance with the relevant requirements of BS 476 : Parts 20 and 22 at a NAMAS accredited laboratory. Independently validated test data from other sources may be accepted at the discretion of the certification body as supplementary information but will not be used as the main basis of the assessment. Fire Test Study Group (UK) resolutions and procedures should be followed.
There is no fixed programme of tests owing to the wide range of sizes, configurations and constructional variables. The testing programme shall, therefore, be designed in conjunction with the certification body to ensure that the scope of certification adequately covers the manufacturer’s requirements. The Assessment Principles, (Section 7), and the Field of Application, (Appendix 1) will provide guidance to enable a suitable test programme to be devised. Typical test configurations are detailed in Appendix 2.
For the evaluation of one particular type of glass for use in one or more proprietary framing system, the system tested should be of a generic design selected to evaluate those parameters critical to the particular glass type. Alternatively, if a proprietary system is selected, it should be done on the basis that features which are critical to the glass type provide the most onerous conditions, if they can be identified, thus providing scope for wider assessment of other systems.
For the evaluation of a particular framing systems it may be possible to select a glass type or types which represent the most onerous situation from which other glass types may be assessed, otherwise the test information may only be applied to glasses with similar properties.
For timber framed systems, which will generally be non-proprietary, a generic, minimal construction may be selected which will form the basis of the assessment of other timber framed constructions. The precise details of the tested construction(s) may vary dependent on the parameters of construction which are critical for the particular glass type under construction, e.g. edge cover.
ASSESSMENT PRINCIPLES
7.1 In order to define the scope of certification an assessment will be conducted based upon available test data. It will examine the following aspects:
(a) The ability of a particular framing system to support the glass(es) for the required fire resistant period.
(b) The ability of the glass to remain in position for a given fire resistance period when suitably glazed.
(c) Compatibility between the glass and frame combination.
(c) The ability of a given pane size to achieve a specific fire resistance period and the ability of the transom to support it.
(e) An indication of the effects of aspect ratio.
(f) The ability of the assembly to accommodate shared transom and mullions.
(g) The effect incorporating a door assembly within an associated structure (glazed wall), if required.
(h) The method of fixing the assembly to a given restraint frame must be appropriate to the nature
of the supporting structure. Consideration must be given to the likelihood of the same framing being fixed to different supporting structures in reality.
(i) The possibility of alternative ancillary items such as glazing gaskets, pointing mastics, decorative trims etc.
The failure of a glazed wall under test conditions may be clearly attributed to either performance of the glass, e.g. slumping from the frame, or performance of the framing system, e.g. ignition on the unexposed face or some form of mechanical or structural failure. The assessment will consider the mode of failure in order to identify the factors which may limit possible design variations. The mode of failure will be critical in determining the extent to which the tested system can be modified or assessed in to a wider field of application.
Assessment of variations from the tested specimens will be on the basis of interpolation except where there is clear indication from the test evidence that extrapolation will not prejudice the required fire resistance performance. For example, a large margin of performance may provide sufficient confidence to permit an increase in size.
Assessments shall be based on information derived from the appropriate test or tests as specified in Sections 5 and 6 and in accordance with the field of application information given in Appendix 1.
Deviation from the field of application rules (Appendix 1) is permitted provided technical justification is given.
AUDIT TEST REQUIREMENTS
To ensure continuing compliance for the certificated end use, audit testing shall be conducted.
For each certificate issued an audit test shall be conducted at not more than three-year intervals.
The audit test shall be to BS 476 : Part 22 on a full scale specimen. The precise design, size and configuration shall be as specified by the certification body but related to the original test programme. Fire resistance tests conducted for other purposes may be accepted in lieu of audit tests at the certification body’s discretion.
If a test result indicates that a system does not meet the expected fire resistance the reason shall be immediately investigated by the certificated company and certification body and agreed corrective action taken. In such circumstances the certification body reserves the right to require a repeat test to be conducted and, if necessary, may terminate, suspend or reduce the scope of its certification.
IDENTIFICATION
The certificate will be issued individually to the manufacturer and included in the annual LPCB List of Approved Fire and Security Products and Services. It will include a description of the product and details of the scope of certification such as fire resistance and maximum pane sizes. Parameters critical to the maintenance of product performance will be specified. These may include edge cover, edge restraint, glazing material, glazing bead detail and allowable framing/glass variants.
Products shall be suitably marked with the relevant certification reference number.
9.3 Each product shall be despatched with a data sheet which clearly includes the following details: o The reference number and scope of certification.
o The storage and handling provisions. o The installation instructions.
INSTALLATION
LPCB certificated products shall be installed in accordance with the specification agreed by the LPCB. Where this is not the case the LPCB logo and reference number shall be omitted and the system shall not be considered as certificated.
MAINTENANCE
This scheme does not cover maintenance of the installed products.
QUALITY
The manufacturer shall demonstrate to the satisfaction of the LPCB that the quality management system under which the products are manufactured and installed is in general accordance with ISO 9001.
The manufacturing base and installation procedure shall be initially inspected by the LPCB and thereafter shall be inspected twice a year for the duration of certification.
POST INSTALLATION INSPECTION
The LPCB reserves the right to make random inspections of installed certificated products. Any certificated products found not to comply with the specification agreed with the LPCB shall be investigated and may result in loss of certification.
COMPLAINTS
Complaints about LPCB certificated products shall be investigated by the LPCB. Where complaints are not resolved to the satisfaction of the LPCB, the LPCB may withdraw certification.
LISTING
Certificated products will be listed in the annual LPCB List of Approved Fire and Security Products and Services.
APPENDIX 1: FIELD OF APPLICATION OF TEST EVIDENCE
The following rules detail the extent to which test data obtained from a particular specimen may be applied to other design variations. They are applicable where the mechanical performance of the framing system depends upon a single material. Where this is provided by a combination of materials acting in conjunction then the scope of certification will be established on an individual case basis.
The rules assume a single change from tested design. Where multiple changes are to be made the cumulative effects will require evaluation as part of the technical assessment.
Deviation from, or additions to, these rules are permitted provided technical justification is given.
ORIENTATION
The approval will cover glass glazed walls oriented +/- 15° from the angle at which they were tested provided the integrity performance achieved exceeded that required by 10%. In the absence of a sufficient overrun, no change is permitted from the angle tested.
ASYMMETRIC GLAZING SYSTEMS
Tests on asymmetrical glazed walls with the glazing beads on the fire side of the construction cover those with glazing beads on the non-fire side of the construction but not vice versa.
HEIGHT
Overriding all increases in the number and/or size of panes is the restriction that approval of any glazed wall is limited to the maximum height tested. This may be increased, subject to these rules, to a maximum of 4 metres if the test was on a full (3m) height specimen.
ASPECT RATIO
A1.4.1 30 minutes fire resistance (insulating and non-insulating glass)
The aspect ratio may be varied without restriction in conjunction with the size increases allowed under A.1.5.1.
A1.4.2 >30 minutes fire resistance (non-insulating glass)
The aspect ratio may be varied without restriction provided that the largest dimension of the pane and the area are not increased after those changes allowed under A.1.5.2.
The aspect ratio may be changed to a more adverse shape by a percentage equal to the period of overrun, provided there is no increase in area. For example, for a 60 minute integrity requirement a 66 minute result would enable a 10% increase in the largest dimension of the pane together with a corresponding reduction in the other dimension so that the area was unchanged.
The percentage overrun may be shared between increasing the pane size and adversely changing the aspect ratio. For example, for a 60 minute integrity requirement, a 72 minute result would enable a 10% increase in area as in above and a 10% adverse change in aspect ratio as specified.
A1.4.3 >30 minutes fire resistance (insulating glass)
The aspect ratio may be varied without restriction in conjunction with the size increases allowed under A.1.5.2.
PANE SIZE
A1.5.1 30 minutes fire resistance (insulating and non-insulating glass)
Metal frames
The dimension of the glass may be increased by up to 25% in height and 25% width providing the framing system, in particular the transom, is able to support the glass.
Timber frames
The dimensions may be increase in the same proportions as the metal frames (see above). In addition, in order to obtain approval for the maximum pane size there must be evidence that the framing system has previously been tested successfully in conjunction with a similar glass of that height and weight.
A1.5.2 >30 minutes fire resistance (insulating and non-insulating glass)
Metal frames
The area may be increased by a percentage equal to the period of overrun with no adverse change in aspect ratio. For example, for a 60 minute integrity requirement, a 66 minute result would enable an increase in area of 10%. In no case shall the permitted pane area increase by more than 25%.
The percentage overrun may be shared between increasing the pane size and adversely changing the aspect ratio. For example, for a 60 minute integrity requirement, a 72 minute result would enable a 10% increase in area as in above and a 10% adverse change in aspect ratio as specified.
For insulated glass, since the insulation performance is independent of pane size, there is no limit on the increase of pane size with respect to insulation performance apart from those resulting from consideration of integrity performance.
Timber frames
The dimensions may be increased in the same proportions as the metal frames (see above). In addition, in order to obtain certification of the maximum pane size there must be evidence that the framing system has previously been tested successfully in conjunction with a similar glass of that height and weight.
NUMBER OF PANES
A number of panes in a glazed wall may be increased provided that there is supporting test evidence of shared mullions and/or transoms as appropriate.
The number of panes in a glazed wall may be decreased provided that the area of any pane does not exceed the maximum allowable under these rules.
EDGE COVER
Non-insulating glasses
Within manufacturing tolerances edge cover may not be decreased. Edge cover may be increased except for edge sensitive glasses. A1.7.2 Insulating glasses
Within manufacturing tolerances edge cover may be increased but not decreased.