LPS 1581 Issue 2.1 Requirements and tests for LPCB approval of non- load bearing external cladding systems applied to the masonry face of a building
This document specifies the fire test and approval requirements for non-load bearing External cladding systems such as rendered insulation, brick slips, rainscreen panel or similar systems applied to the masonry face of a multi-story building.
This standard applies to systems installed on masonry faced constructions, as either refurbishment or new build.
This standard does not address systems applied to structural framed buildings which are covered by LPS 1582 Requirements and Tests for LPCB approval of Non-load bearing External Cladding Systems fixed to and supported by a structural steel frame.
A schematic sketch of typical system types is shown in figures 1 and 2.
For the purposes of this standard the definitions contained in BS 8414-1 Fire performance of external cladding systems, Part 1: Test method for non-loadbearing external cladding systems applied to the face of the building, apply.
The applicant shall supply the following documented information:
- A schematic description of the system to identify each component and layer used.
- A complete set of production drawings (where applicable) and installation drawings relevant to the system submitted for test and approval including all proposed variations.
- Full specification of all components used in the production and installation of the system. This shall include details of the component manufacturers, part numbers, data sheets and all fire performance characteristics to EN 13501-1 Fire classification of construction products and building elements. Part 1: Classification using test data from reaction to fire tests and EN 13501-2 Fire classification of construction products and building elements – Part 2: Classification using data from fire resistance tests, excluding ventilation services, as appropriate.
- Full installation instructions as supplied to the installation contractors.
Initial type testing requirements
System reaction to fire classification
For each complete system subject to approval, a reaction to fire classification in accordance with BS EN 13501-1 shall be determined.
Glowing combustion – Insulation
All insulation materials will be assessed for potential glowing combustion prior to acceptance for approval by LPCB. Where appropriate these will be tested against the ramped basket test as detailed below, where products are shown to exhibit glowing combustion, the system criteria given in section 4.1.7 will be applied.
Ramped Basket Test
The test is carried out in a mechanically ventilated oven with an inner chamber of sufficient size to accommodate the test piece and allow free air circulation around it.
A cubical wire mesh basket measuring 100mm on each edge is filled with the material under test and a 0.5 mm stainless steel sheathed chromel/alumel thermocouple is inserted into the centre of the sample to monitor the central temperature. The filled cube is then suspended in the oven together with a second thermocouple to register oven temperature. The thermocouples shall be connected to a data acquisition system capable of recording data at a minimum of 10 s intervals.
The screening test is run over a 24 hour period. The temperature of the oven is set to increase at a nominal rate of 0.5oC per minute from room temperature up to a maximum of 400oC. Once the temperature has been attained the oven is maintained at this temperature for the remainder of the 24 hour period. The central thermocouple will detect any exothermic reaction where the temperature increases independently of the oven temperature. The onset of an exotherm may be measured by determining the temperature at which the central temperature exceeds the oven temperature crossing point.
Full Scale System Test
The specification of the test specimen shall be agreed between the applicant and LPCB. These details shall be provided to LPCB as detailed in section 3.1.
The client shall be responsible for the installation of the system as detailed in their submitted documentation.
Full scale test method
The test arrangement shall be as described in BS 8414-1.
The conditioning and test environment shall be as specified in BS 8414-1.
In addition, all tests shall be undertaken in a suitable test building and the test faces shall be a minimum of 3m from any reflecting surface.
Test procedure and Reporting
The test shall be carried out to the procedure and reported fully in accordance with the BS 8414-1. The timber crib ignition source specified in BS 8414-1 Annex B shall be used for all tests.
A crib collapse zone shall be marked on the floor of the test facility. This shall be 2.4m x 1.2m in area and positioned centrally on the centre line of the hearth opening (2.4m length parallel to the face of the hearth). In addition to the general observations required by BS 8414-1 regarding system performance during the test; any droplets, debris or collapse to the floor shall be reported with reference to this marked area.
In addition, a full video record of the test shall also be taken and supplied to LPCB with the laboratory test report.
Component Fire Test Data
These tests are used to establish the baseline fire performance characteristics of the system components for ongoing auditing and system verification.
These tests are used for quality control purposes and are not part of the system performance requirements.
Samples of the insulation from the full scale test programme shall be taken by the laboratory and submitted for test.
The test protocols used to establish and verify the baseline fire performance characteristics of the insulation material shall be determined by LPCB based on the most appropriate methodology for the type of insulation material.
External finish systems
The Gross Calorific Value (PCS) for all external finish systems including basecoats and meshes, as applicable, shall be determined using EN 1716 Reaction to fire tests for building products – Determination of the heat of combustion. These values shall be used to establish and verify the baseline fire performance characteristics for the external finish system.
Early test termination
Failure of the system is deemed to have occurred if the test is terminated within the duration of the full test period for any safety reason.
Failure of the system is deemed to have occurred if visible flaming, which exceeds the confines of the test rig either vertically or laterally during the full 60 minute test period, is observed. For the purposes of this clause, visible flaming is defined as a continuous flame which is observed for more than 60 seconds duration (i.e. not intermittent or glowing)
External fire spread
Failure due to external fire spread is deemed to have occurred if the temperature rise above Ts of any of the external thermocouples at level 2 exceeds 600°C for a period of at least 30 seconds, within 30 minutes of the start time ts.
Internal fire spread
Failure due to internal fire spread is deemed to have occurred if the temperature rise above Ts of any of the internal thermocouples at level 2 exceeds 600°C, for a period of at least 30 seconds, within 30 minutes of the start time ts.
Failure will be deemed to have occurred if there is collapse of the system or part thereof, flaming or not, onto the floor of the test facility outside the designated crib collapse zone, see note 1, within the duration of the full 60 minute test period.
Burning debris and pool fires
Failure is deemed to occur if burning debris or a pool fire develops on the floor of the test facility, outside the designated crib collapse zone, see note 1.
Burning debris is defined as visible flaming for more than 60 seconds duration (i.e. not intermittent or glowing) within the duration of the full 60 minute test period.
Note 1: The crib collapse zone is defined as a 2.4m x 1.2m positioned centrally on the centre line of the hearth opening (2.4m length parallel to the face of the hearth).
Where an insulation product exhibits the propensity for glowing combustion, the system design shall restrict the potential spread of self-propagating combustion within the insulation vertically beyond subsequent floor levels and laterally beyond the line of internal compartment walls.
Failure in relation to this standard is deemed to occur if the area of system damage spreads vertically beyond level 2 or reaches the outer edge of the wing wall, in the area between Level 1 and Level 2, within 24 hours of the termination of the full 60 minute test period.
Field Of Application Of Test Results
Type of system tested
The test results apply to the specific system specification as tested.
In order to cover a range of insulation thicknesses, the thinnest and thickest insulation for a given system type, where all other system specifications remain unchanged, shall be tested. Where only one thickness is tested, the LPCB approval will be limited to that thickness.
The range of cavity depths and associated closure systems shall be declared on application as part of section 3.1. Typically, in order to cover a range of cavity depths, where all other system specifications remain unchanged, the minimum and maximum
depths shall be tested. Where only one depth is tested, the LPCB approval will be limited to that depth.
The test result will only apply to the density tested. If various densities are available, further evaluation will be required.
Change in inner leaf
The test uses a masonry wall as the inner leaf. Other types of leaves fall outside the scope of this standard.
Position of fire breaks
Where fire breaks are employed, test results will only apply to the type, fixing and position arrangements as tested. The spacing of fire breaks will be limited up to the maximum spacing as tested.