text: fig3 shows a flexible component 100 in accordance with an example of the invention . the middle portion of fig3 is cutaway to show a cross section through the component 100 . fig4 shows a cross - section through the fig3 component in the ae - ae plane . the component 100 shown in fig3 comprises a core element 110 . as with all embodiments , the core element 110 may be any suitable component , for example a flexible component and / or a component that requires heat / fire protection . examples of a core element include pipes , cables , wires and flexible printed circuits , as in the examples shown in the figures . the core element 110 is surrounded by a heat protection assembly 140 . the heat protection assembly comprises a coil wrap 120 . the coil wrap 120 is an intumescent coil wrap . the heat protection assembly may also comprise an impermeable layer 130 which may be flexible , as in the fig3 example . as shown in fig3 , the flexible impermeable layer 130 ( which may , for example , comprise silicon ) may be positioned between the core element 110 and the coil wrap 120 . the flexible impermeable layer 130 may provide protection to the core element 110 against fluid ( for example liquid ) ingress . the coil wrap 120 may be formed in any suitable manner . for example , it may be preformed to match the cross - sectional profile of the combined core element 110 and flexible impermeable layer 130 , or a length of intumescent material may be wrapped around the combined core element 110 and flexible impermeable layer 130 to create the coil wrap 120 . the coil wrap 120 is arranged ( for example by having a suitable pitch p and / or width w ) such that a coil - shaped gap 150 is formed . in the coil - shaped gap 150 , the flexible impermeable layer 130 may be exposed , and thus may not be covered by the intumescent wrap material . this coil - shaped gap 150 may allow the component 100 to be flexible and / or improve the flexibility of the component 100 . for example , even if the intumescent material of the coil wrap 120 is substantially rigid , or inflexible , ( which may or may not be the case ) the component 100 may retain flexibility as a result of the coil - shaped gap 150 formed by the arrangement of the coil wrap 120 . the core element 110 may be an elongate core element 110 with a longitudinal axis x - x , as in the examples shown in the figures . the coil wrap 120 may fit loosely around the core element 110 , or around the combined core element 120 and flexible impermeable layer 130 and core element 110 , as in fig3 . thus , the coil wrap 120 may be free to move relative to the core element 110 and optionally the flexible impermeable layer 130 , for example axially in the x - x direction . this may allow the coil - shaped gap 150 to change width q ( or open and close ) depending on the shape of the flexible component 100 . the width q of the coil - shaped gap 150 may thus vary along the length of the component 100 , for example as the component 100 is flexed . indeed , the variable width q may allow the component 100 to flex , or at least improve its flexibility . purely by way of example only , the width w of the coil wrap 120 may be in the range of from 1 mm to 50 mm , for example 2 mm to 40 mm , for example 3 mm to 30 mm , for example 4 mm to 20 mm , for example 5 mm to 10 mm , for example on the order of 6 mm . of course , widths w greater than 50 mm or less than 1 mm may be used , depending on the application . purely by way of example only , the width q of the coil - shaped gap 150 ( when the component 100 is not flexed , for example ) may be in the range of from 0 . 1 mm to 10 mm , for example 0 . 2 mm to 5 mm , for example 0 . 5 mm to 2 mm , for example on the order of 1 mm . of course , widths q greater than 10 mm or less than 0 . 1 mm may be used , depending on the application . as mentioned above , the coil wrap 120 may comprise an intumescent material . such an intumescent material may ( or may not ) be provided with a backing material , such as a nomex ® based material . the backing material , if present , may help to provide support for the intumescent material in the event of a fire . any suitable intumescent material may be used . purely by way of example , the intumescent material may comprise technofire 2000 ® or technofire 2006 ®. the thickness of the wrap material may depend on the application . for example , the thickness may be in the range of from 0 . 05 mm to 5 mm , for example 0 . 1 mm to 2 mm , for example 0 . 2 mm to 1 mm , for example on the order of 0 . 5 to 0 . 65 mm . of course , the thickness may be greater than 5 mm or less than 0 . 05 mm , depending on the application . in the event that the intumescent material is exposed to a temperature above its activation temperature ( for example in the event of a fire , either through exposure to a flame or to hot gas produced from a fire ), the intumescent material may expand . fig5 shows such an expanded , or swollen , intumescent layer 120 ′. the fig5 view is a similar cross - section through the component 100 to that shown in the middle portion of fig3 . the expanded intumescent layer 120 ′ forms a heat - protection , thermal protection and / or fire - protection layer . the expanded intumescent layer 120 ′ may surround the core element 110 . the expanded intumescent layer 120 ′ may also surround the flexible impermeable layer 130 , where present , as shown in the fig5 example . the expanded intumescent layer 120 ′ may have no axial spaces , or gaps . thus , for example , during expansion the coil - shaped gap 150 may be closed . the expanded intumescent layer 120 ′ may ( or may not ) reduce , or substantially remove , any flexibility of the original component 100 . however , this may not be important after a fire , where the emphasis may be placed more on protecting the core component 110 than retaining flexibility . thus , above the activation temperature , the expanded intumescent layer 120 ′ may thus form a thermal protection layer 120 ′. this thermal protection layer 120 ′ may be complimented by the flexible impermeable layer 130 , i . e . the flexible impermeable layer 130 may also provide thermal protection . various arrangements of components are provided according to the invention . fig6 to 8 relate to an example of one such flexible component 200 . the flexible component 200 shares various features and / or properties with the flexible component 100 described above in relation to fig3 to 5 , and like features are given the same reference numerals , and will not be described again in relation to fig6 to 8 . the flexible component 200 of fig6 and 7 comprises a protective layer 210 covering the intumescent coil wrap 120 . the protective layer may provide environmental and / or abrasion protection to the intumescent wrap 120 , for example . the protective layer 210 may comprise , for example , an elastomer , such as silicon and / or rubber . the protective layer 210 may take any form , for example the protective layer 210 may form a coil shape that corresponds to the intumescent coil wrap 120 that it protects . the protective layer 210 may or may not be considered to form part of the heat protection assembly 240 . fig8 shows the component 200 of fig6 and 7 after the intumescent coil wrap has been exposed to a temperature above the activation temperature . as with the other embodiments , the intumescent material has expanded in fig8 to form a thermal protection layer 120 ′. additionally , the protective layer 210 ′ may expand with the intumescent material to provide further thermal and / or mechanical and / or abrasion protection . the protective layer 210 ′ may form an ablative layer after the component 200 is exposed to a temperature above the activation temperature . the protective layer 210 may be provided to any example of the invention including , by way of example , those shown in the figures . fig9 to 11 show a further example of a component 300 according to the invention . again , the example of fig9 to 11 shares various features / properties of other embodiments , and like features are given the same reference numerals and will not be described again in relation to fig9 to 11 . the flexible component 300 of fig9 and 10 comprises a layer 130 that comprises one or more coil - shaped ribs 134 . the layer 130 may be an impermeable layer , which may be flexible . the coil - shaped rib 134 extends from a spine 132 of the flexible impermeable layer 130 . the intumescent coil wrap 120 sits in coil - shaped grooves formed by the coil - shaped rib 134 . the coil - shaped grooves may thus be said to form a coil - shaped gap interlaced with the coil wrap 120 . optionally , the intumescent coil wrap 120 may be fixed , for example bonded , to the base 135 of the grooves . for example , the coil wrap 120 may be bonded to the base 135 of the grooves using a suitable adhesive , such as fastblock 100 ® or any other suitable rtv adhesive . locating the intumescent coil wrap 120 in the grooves or troughs may help to ensure that the desired pitch / spacing of the wrap is achieved . additionally , the rib ( s ) 134 may provide protection to the coil wrap 120 , for example against abrasion . the dimensions of the grooves , ribs 134 , and intumescent coil 120 may be chosen to be as required for a particular application . fig1 shows the component 300 after exposure at or above the activation temperature of the intumescent material . in a similar manner to that described above in relation to other examples , the intumescent material 120 has expanded to form a thermal protection layer 120 ′. the thermal protection layer 120 ′ may form a continuous layer , as shown in the fig1 example . as with the other examples , the coil - shaped gaps interlaced with the intumescent coil 120 may be closed when the intumescent material expands at the activation temperature . thus , the thermal protection layer 120 ′ may cover the flexible impermeable layer 130 , including the ribs 134 . the thermal protection layer 120 ′ may thereby provide thermal protection to the core element 110 at least . a protective layer 210 may be applied to a flexible component having ribs 134 , as shown in the example of fig1 and 13 . the protective layer 210 may take any suitable form , and may be as described above in relation to fig6 , 7 and 8 . for example , the protective layer 210 may be a continuous layer that surrounds the rest of the flexible component 400 , or may be a coil shape the corresponds to , and sits on , the coil wrap 120 , as shown in example of fig1 and 13 . the description in relation to fig6 , 7 and 8 applies to the example of fig1 and 13 , and will not be repeated here . fig1 to 16 relate to an example in which the flexible component 500 is provided with porous layer 510 . the porous layer 510 may be part of the heat protection assembly 140 . a porous layer 510 may be applied to any arrangement of the invention . for example , a porous layer may be provided to an arrangement comprising a flexible impermeable layer which has ribs 134 ( as in the example shown in fig1 ) or to an arrangement comprising a flexible impermeable layer which does not have ribs ( for example a porous layer may be applied to the arrangements discussed in relation to fig3 to 8 ). a porous layer 510 may be provided in addition to , or instead of , a further protective layer 210 , such as that discussed in relation to fig6 - 8 , 12 and 13 . in the example of fig1 to 16 , the porous layer 510 is provided without an additional protective layer 210 . the porous layer may , for example , comprise polyetheretherketone ( such as peek ), and / or an organic composite fibre matrix , such as a carbon fibre weave . the porous layer 510 itself may be substantially flexible , and so may not limit the overall flexibility of the component 500 . the porous layer 510 may be provided in any suitable manner , for example wrapped around other parts of the component 500 or provided as a “ sock ” that fits over other parts of the component 500 . because the layer 510 is porous , it may not retain liquid during normal operation . if the intumescent material of the coil wrap 120 is exposed to a temperature above its activation temperature , it may swell , or expand , substantially as described above in relation to other examples and as shown in fig1 . when the intumescent material expands , it may extend into , or fill , at least some of the voids in the porous layer , thereby impregnating the porous layer 510 . this may enhance the fire protection provided to the core element 110 . such a porous layer 510 may thus provide enhanced durability ( e . g . abrasion resistance ) during normal use ( below the activation temperature ) and / or in the event of exposure to excessive heat and / or may provide enhanced heat protection , for example in the event of a fire . aspects of the invention may be provided to and / or comprise any component that may require heat ( for example fire ) protection , for example any such component on an engine , such as a gas turbine engine . the present invention may be applied in technical fields such as ( by way of example only ) defence , aerospace , automotive , rail , marine , civil engineering , power generation , petrochemical , chemical , biological , manufacturing , nuclear or any other field which requires heat protection of a component . where the invention is applied to a gas turbine may typically have to withstand continuous operating temperatures between − 65 and + 150 ° c . and exposure to fluids such as kerosene , aviation gasoline ( avgas ), natural gas , hydraulic fluid , lubricating oils and greases etc . components according to the present invention may be adapted to operate in such environments . for example the materials may be selected to withstand such an environment . nevertheless , different materials may be selected to allow the assembly to operate in hotter or cooler environments or to withstand exposure to other chemicals encountered in different applications . various alternative and / or complimentary arrangements and / or components not explicitly described herein are in accordance with the invention . for example , although the description is provided mostly in relation to a flexible core element 110 , the present invention may also be applied to non - flexible core elements , eg rigid core components , for example to provide a heat protection system with sufficient protection but reduced weight . furthermore , any compatible feature or description provided herein in relation to one example may apply to and / or be provided to any other example .