Method Statement FM MS 09 SSCB

Transcription

1 FMFM FM Method Statement FM MS 09 SSCB Fire Protection of structural steelwork with the FireMaster Blanket Structural Steel PFP system in accordance with the EU CPR English Rev 1: March 2018 FM

2 CONTENTS 1 Introduction and Overview of system concept 2 Design of the system 21 Identification of steel section geometry and calculation of section factor 22 Identification of the steel critical temperature and protection time to be maintained 23 Selection of FireMaster blanket thickness 24 Key design features of the system 3 Installation 31 General Information 32 Anchor Pins and Washers 33 Installation Method Single Layer Systems on columns 34 Installation Method Single Layer Systems on beams 35 Installation Method: - Multiple Layer Systems 4 Installation Techniques APPENDICES 1 Declaration of Performance Document 2 UL Europe Certificate 3 European Technical Assessment Document 4 Product Data Sheet : FireMaster Marine Plus Blanket

3 1 Introduction and Overview of system concept The FireMaster structural steel fire protection system consists of a non-combustible, flexible, fire-insulating blanket which is wrapped around the exterior profile of structural steel sections and held in place using welded steel anchors and friction fit washers The blanket is lightweight (96 kg/m³ density) and applied in one or two layers depending on the steel section factor, required critical temperature and the fire protection time rating required The system is classified for fire protection in the range of R30 to R180 in accordance with EN based on fire testing to : 2013 standard and certified by UL Europe in accordance with the requirements of ETAG 018-4:2011 The Certificate of Conformity document issued for compliance with the EU Construction Products Regulation (CPR) and a copy of the certificate issued for the system by UL Europe are included in the Appendix to this Method Statement 2 Design of the system The elements of system design are as follows: Identification of the steel section geometry Identification of the heated perimeter and sectional area of the steel section required to calculate the steel section factor (commonly referred to as Hp/A, or A/V or F/A) Identification of the steel critical temperature limit to be maintained Specification of the fire protection time period required Selection of required blanket thickness to meet the above criteria Selection of the number of layers of blanket that are required to be installed (one or two) Specification of the installation technique for the steel section and required number of layers in accordance with this document Morgan Advanced Materials provides a software package called SectionWizard to simplify the design of blanket thickness requirements for the FireMaster Structural Steel System This software is available on request It contains a database of standard steel section shapes and automatically calculates the section factor and then selects the required blanket thickness and number of layers required for any time periods within the system certified limits Use of this software avoids the time required to calculate section factors and consult tables of section factor v temperature v protection time 21 Identification of steel section geometry and calculation of section factor Steel sections may be one of several different shapes ie H beam, flanges, angles, circular or rectangular hollow sections etc The section factor concept relates the surface area of the steel section exposed to fire to the cross-sectional area available to absorb heat from the fire and is commonly referred to using one of the following abbreviations: Hp/A, F/A or A/V

4 Steel sections with larger section factors will exhibit faster temperature rise in a fire than those with smaller section factors as the ratio of area receiving heat from a fire to the mass of steel available to absorb that heat is higher Section Factors are calculated by dividing the external fire-exposed perimeter of the steel section by its cross sectional area The example below compares the section factors of two 305 x 305 steel columns, exposed to fire on all sides It can be seen that the section factor varies significantly, the 305 x 305 x 97 column is thinner and has less steel mass available to absorb heat from a fire It will therefore heat up faster than the 305 x 305 x 198 column Because of this, more fire insulation will be required to provide the same level of fire protection When calculating section factors, it is important to remember that the only heated perimeter of the section should be considered For example, if a steel beam is supporting a roof, the upper flange of the beam will not be heated (ie exposed to fire) and this portion of the steel section should not be used in the calculation of the heated perimeter However the entire cross-sectional area is available to absorb heat and therefore the section factor will be reduced compared to a the same section when fully exposed to fire

5 22 Identification of the steel critical temperature and protection time to be maintained Steelwork is insulated against fire to maintain its temperature below a specified critical temperature limit to ensure its loadbearing function is maintained during fire exposure The required critical temperature and protection time required is generally specified by the body responsible for the structural design of the building with reference to applicable building codes and regulations There are both prescriptive approaches and performance-based approaches applied to identify these temperature limits The typical prescriptive approach specifies the thickness of fire protection to steel elements to ensure the steel does not exceed a specified temperature for a given fire resistance period For example, in the UK, the maximum temperatures of 550 C for columns and 620 C for beams supporting concrete floors are assumed These temperatures are based on the assumption that a fully-stressed member at ambient conditions (designed to BS or BS449) will lose its design safety margin when it reaches the maximum temperatures The performance based approach involves the assessment of three basic components comprising the likely fire behaviour, heat transfer to the structure and the structural response The overall complexity of the design depends on the assumptions and methods adopted to predict each of the three design components This approach may result in different critical temperatures being identified than when using the prescriptive approach The time of protection is simply the duration (usually in minutes) that the steel section temperature must not exceed the critical temperature that has been specified 23 Selection of FireMaster blanket thickness The required thickness of blanket can be identified from tables that are included as part of the UL certification for the system These tables are included in the Appendix to this document For each time period, a table is published showing the thickness of blanket required to maintain a range of critical temperatures for various section factors For blanket thicknesses up to 52mm, the blanket can be installed in a single layer For blanket thicknesses of more than 52mm, two layers must be installed with a minimum total thickness of 60mm applied In all cases, the required density of blanket is 96 kg/m³ A technical data sheet for the FireMaster blanket used in the system is included in the Appendix to this document The thickness tables included in the certification identify the minimum blanket thickness to be applied to meet the required level of fire protection The blanket is manufactured in a range of standard thicknesses Therefore in some cases, more thickness of blanket may need to be installed than the minimum required shown in the tables because the next, higher, standard blanket increment will have to be used The standard blanket thickness range is as follows:

6 13mm, 20mm, 25mm 38mm50mm, 60mm So for example if 47mm is required then 50mm would be used in practice However, blanket can be made in any thickness increment in the range 6mm up to 60mm Therefore for large volume projects it may be possible to arrange for the blanket to be supplied to the exact thickness required The local Morgan Advanced Materials sales office can provide advice on the minimum order quantities for this 24 Key design features of the system Fire protection periods: 30 to 180 minutes Steel Critical temperature range: 150 C to 700 C Steel preparation required: Number of layers allowed: Installation Method: Intended design Life: None Single layer (maximum thickness 52mm) or two layers (minimum thickness 60mm) Blanket wrap around the profile of the section For H beams the outer profile of the section is wrapped 25 years Intended use environment: Internal only (Z2 as defined in ETAG 018-4:2011) May be installed on: Beams, columns, hollow sections, sections with re-entrant details (eg channels, angles, tees) 3 Installation 31 General Information The first step is to weld anchor pins to the steel section The anchor pins are used to hold the blanket in place onto the steel along with friction-fit washers 32 Anchor Pins and Washers The anchor pins used are normally coper-coated mild steel of 3mm shaft diameter They are attached using CD welding The anchor pin length should be sufficient to install the retaining washer without over-compressing the blanket An anchor pin length of 12mm to 25mm greater than the blanket

7 thickness should be sufficient to avoid over-compression This additional length can be reduced through the use of a washer installation tool (see details of this below) A 38mm diameter zinc-coated mild steel friction fit washer is used with the anchor to retain the blanket in place A custom-designed washer installation tool (illustrated below) is available from Morgan Advanced Materials for fast installation of the washer This tool allows control of the point along the anchor shaft where the washer is fixed allowing the anchor pin length to be shorter than that required when the washer is manually installed Alternatively, the washer can be applied by hand The positions of the anchor pins depend on section size and FireMaster blanket thickness installed The anchor pin locations for various section sizes are described in Section 33 below

8 33 Installation Method Single Layer Systems on columns For thicknesses up to 52mm, the blanket is applied in a single layer The blanket is fitted around the perimeter of the section There must be sufficient free space for it fit completely inside the web on H shaped beams and columns as shown in Figure 1 below Figure 1: Arrangement of anchor pins on small and large H/I shaped columns 331 Large Size Sections In the web of the column anchors pins are spaced at 150mm Anchors are spaced at 150mm centres on larger flanges and the blanket joint positioned centrally between them (ie 75mm from the anchor pin) 332 Small Size Sections When there is insufficient space to fit two pins at 150mm centres in the web on smaller sections, then one pin may be used positioned at the centre of the web On flanges, one anchor pin is installed centrally on the flange Two anchors, spaced 100mm apart, are fitted where there is a blanket joint

9 The blanket is normally supplied in widths of 610mm Joints between each width of blanket are slightly compressed to form a tight fit This is achieved by arranging the anchor pin pattern to a theoretical blanket width of 580mm which produces an overlap of 15mm at each edge of the blanket The blanket is pulled outwards at the edge and each edge squeezed together to form a tight compressed joint The anchor locations across the blanket width are shown in Figure 2 below Figure 2: Anchor pin pattern and blanket joint layout for columns using one or two anchors Blanket is supplied 610mm wide and compressed to form 580mm widths The anchor pins are located 50mm from each blanket edge joint with one anchor in in the middle

10 34 Installation Method - Single Layer Systems on Beams 341 General For thicknesses up to 52mm, the blanket may be applied in a single layer The blanket is fitted around the perimeter of the section There must be sufficient free space for it to fit completely inside the web on H shaped beams and columns as illustrated in Figure 3 below 342 Large Sized Sections In the web of the beam anchor pins are spaced at 150mm with any blanket joint required positioned centrally in the web Refer to Figure Small Sized Sections As there is insufficient space to fit two pins at 150mm centres in the web on smaller sections, then one pin may be used, positioned at the centre of the web On small beams it is unlikely that a joint will be required as the blanket should be of sufficient length to wrap the entire perimeter In the rare event that a joint is required, this can be made by adding an extra pin in the web at a shorter distance than the normally used 150mm and positioning the joint in-between the two anchors in the web 344 Installation along the beam length The blanket is supplied in widths of 610mm On the length of the beam, joints between each width of blanket are slightly compressed to form a tight fit This is achieved by arranging the anchor pin pattern to a theoretical blanket width of 600mm which produces an overlap of 5mm at each edge of the blanket The blanket is pulled outwards at the edge and each edge squeezed together to form a tight compressed joint See Figure 4 for the anchor pin fixing detail

11 Figure 3 Installation of blanket into beams The method is generally the same as for columns except for the location of joints and the fixing onto the supported soffit Joints can be placed in between the anchors in the web Joints will only be required on very large beams as the blanket length is normally sufficient to wrap the whole beam perimeter To fix the blanket to the soffit, use suitable concrete fixing anchors The location of these anchors will vary slightly depending on blanket thickness They should be installed so that the blanket can cover the edge of the beam flange fully as shown and extend onto the soffit by a distance sufficient to allow installation of the washer onto the fixing pin For the spacing of anchors along the beam see Figure 4 below

12 Figure 4: Installation of blanket along beams (single anchor and two anchors) The blanket is installed in a similar arrangement to columns, in compressed widths of 600mm from the as-supplied width of 610mm Anchor pin spacing is 150mm as shown in the drawing 345 Installation on beams with stiffening webs On beams with stiffening webs, the blanket is installed so that it fits over the web The general anchor pin spacing detail shown in Figure 4 is utilised to allow one full width of 610mm blanket to be installed over the stiffener and fixed either side of it Figure 5 shows the single 610mm wide piece of blanket installed over the stiffener and then fixed onto the anchor pins The stiffener webs can be insulated before the entire beam is completed as shown in figure 6 below,

13 Figure 5: Installation of blanket over stiffener web Figure 6: Installation of all stiffener webs before the rest of the beam is completed Figure 7: Competed installation of blanket over beam with stiffener webs

14 35 Installation Method: Multiple Layer Systems For fire protection thickness requirements greater than 52mm, the system must be installed using two layers of blanket The general installation technique is the same as for single layer systems except when considering the location of joints; which must not occur at the same location in both layers Figure 8 below shows a typical arrangement for beams with two layers of blanket fitted Figure 8: Installation of two layer blanket system on beams

15 Figure 9 below shows a typical arrangement for columns with two layers of blanket fitted Figure 9: Installation of two layer blanket system on columns Ensure that the joints along the length of the columns and beams for each layer are offset by a distance of 300mm on beams and 290mm on columns (ie half the width of the blanket installed) See Figures 10 and 11 below

16 Figure 10: Location of offset joints on columns when two-layers of blanket are installed

17 Figure 11: Location of offset joints on beams when two-layers of blanket are installed

18 4 Installation Techniques The blanket may be cut using a standard insulation knife To ensure a good fit of the blanket around the section, follow the procedure in example installation shown below Measure the length of blanket required using the perimeter of the steel section as an initial guide Check that this length of blanket can fit around the section and if not, adjust the length until a good fit is achieved and then use this blanket length as the guide for cutting subsequent lengths Cut a new piece of blanket and then install that piece following this guide Mark the centre of the cut piece and install it over the anchor on the flange as shown above with the mark aligned with the anchor pin Wrap one side of the blanket around the column and fix it onto the anchor pin on the opposite flange Fix into place using a friction fit washer Repeat the same method to wrap the other side of the column

19 Push the blanket into the web of the section impaling it over the anchor pin and using the friction fit washer to fix securely in place The blanket should form a tight fit into the web of the column if the length has been adjusted correctly as described above

20 The next piece of blanket is then fitted ensuring there is a small overlap at the edge of the adjacent blankets The edge of both blankets is then squeezed together to form a tight butted joint

21 Any excess anchor length protruding from the blanket can be removed by cutting or bending the anchor pin over as illustrated above

22 APPENDICES 1 Declaration of Performance Document 2 UL Europe Certificate 3 European Technical Assessment Document 4 FireMaster Marine Plus Blanket Data Sheet