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Concrete screw with countersunk head W-BS/A4
Highest load capacities and efficient mounting. For flush mounting of e.g. railings or handrails in concrete, A4 stainless steel
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![](https://media.wuerth.com/source/eshop/stmedia/wuerth/images/std.lang.all/resolutions/category/78px/819973.jpg)
![](https://media.wuerth.com/source/eshop/stmedia/wuerth/images/std.lang.all/resolutions/category/78px/4718153.jpg)
![](https://media.wuerth.com/source/eshop/stmedia/wuerth/images/std.lang.all/resolutions/category/78px/37850891.jpg)
![](https://media.wuerth.com/source/eshop/stmedia/wuerth/images/std.lang.all/resolutions/category/78px/574255612.jpg)
Variants
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- Extremely flexible to use due to three anchoring depths (size 6-10)
- Fastening can be adjusted up to twice after installation (size 6-10), for example in order to align railings or anchor plates (please refer to the assembly guide)
- Very high loads
- Smallest axial and edge clearance due to very low expansion effect
- Very fast and easy assembly and immediately load-bearing
- Attractive, flush-mount installation possible
European Technical Assessment ETA-16/0043 for fixing point, option 1, cracked and non-cracked concrete:
- Static and quasi-static effects (∅6 - ∅10)
- Seismic effect, performance category C1 (∅6 - ∅10)
- Fire resistance R30, R60, R90, R120
European Technical Assessment ETA-16/0128 for anchors in a redundant non-structural system:
- Cracked and non-cracked concrete, (∅6)
- Hollow-core prestressed concrete ceilings C30/37 - C50/60, (∅6)
- Fire resistance R30, R60, R90, R120
DIBt National technical approval/general type approval Z-21.1-2075 as bonded screw anchor for anchoring in concrete (∅10, type S hexagon head)
- Use in combination with injectable mortar WIT-BS as bonded screw anchor WIT-BS
- In reinforced and non-reinforced and cracked and non-cracked concrete C20/25 to C50/60
Tensile capacity in concrete hollow body ceilings, (∅6 - ∅10) - expert report no. 21641 - 2016
Fire resistance rating when exposed to fire according to the uniform temperature time curve in masonry (Mz, KSL, KS), and reinforced concrete, (∅6) - expert report no. 2101/173/18 - 2018
From size 8, we recommend the use of a suitable tangential impact screwdriver for installation. The recommended nominal torque must be observed. When used outdoors, the drill hole can be sealed with WIT-BS injectable mortar.
![](https://media.wuerth.com/stmedia/wuerth/images/std.lang.all/resolutions/normal/348px/4206421.jpg)
Railings
![](https://media.wuerth.com/stmedia/wuerth/images/std.lang.all/resolutions/normal/348px/4206422.jpg)
Handrails
![](https://media.wuerth.com/stmedia/wuerth/images/std.lang.all/resolutions/normal/348px/4332957.jpg)
Adjustment - subsequent aligning possible
![](https://media.wuerth.com/stmedia/wuerth/images/std.lang.all/resolutions/category/348px/37435254.jpg)
Create the drill hole
![](https://media.wuerth.com/stmedia/wuerth/images/std.lang.all/resolutions/category/348px/12162590.jpg)
Clean the drill hole
![](https://media.wuerth.com/stmedia/wuerth/images/std.lang.all/resolutions/category/348px/12162589.jpg)
Place screw
![](https://media.wuerth.com/stmedia/wuerth/images/std.lang.all/resolutions/category/348px/12162588.jpg)
Screw in the screw
![](https://media.wuerth.com/stmedia/wuerth/images/std.lang.all/resolutions/category/348px/12162587.jpg)
Considered installed when the head is close fitting
![](https://media.wuerth.com/stmedia/wuerth/images/std.lang.all/resolutions/category/348px/12162586.jpg)
Screw out the screw max. 2x each by max. 10 mm. Underlay. Screw in
![](https://media.wuerth.com/stmedia/wuerth/images/std.lang.all/resolutions/category/348px/12162592.jpg)
Considered installed when the head is close fitting. Lining max. 10 mm. The required embedment depth must be maintained as a minimum
![](https://media.wuerth.com/stmedia/wuerth/images/std.lang.all/resolutions/category/348px/3662258.jpg)
Locate the tensioning strand
![](https://media.wuerth.com/stmedia/wuerth/images/std.lang.all/resolutions/category/348px/3662259.jpg)
Mark the tensioning strand and locate the next one
![](https://media.wuerth.com/stmedia/wuerth/images/std.lang.all/resolutions/category/348px/3662260.jpg)
Mark the tensioning strands. Specify the drilling range
![](https://media.wuerth.com/stmedia/wuerth/images/std.lang.all/resolutions/category/348px/3662261.jpg)
Create the drill hole. Observe spacing
![](https://media.wuerth.com/stmedia/wuerth/images/std.lang.all/resolutions/category/348px/3662262.jpg)
Clean the drill hole
![](https://media.wuerth.com/stmedia/wuerth/images/std.lang.all/resolutions/category/348px/3662263.jpg)
Screw in the screw
![](https://media.wuerth.com/stmedia/wuerth/images/std.lang.all/resolutions/category/348px/3662264.jpg)
Considered installed when the head is close fitting. Observe the embedment depth/mirror thickness
European Technical Assessment ETA-16/0043 for fixing point, option 1, cracked and non-cracked concrete:
- Static and quasi-static effects (∅6 - ∅10)
- Seismic effect, performance category C1 (∅6 - ∅10)
- Fire resistance R30, R60, R90, R120
European Technical Assessment ETA-16/0128 for anchors in a redundant non-structural system:
- Cracked and non-cracked concrete, (∅6)
- Hollow-core prestressed concrete ceilings C30/37 - C50/60, (∅6)
- Fire resistance R30, R60, R90, R120
DIBt National technical approval/general type approval Z-21.1-2075 as bonded screw anchor for anchoring in concrete (∅10, type S hexagon head)
- Use in combination with injectable mortar WIT-BS as bonded screw anchor WIT-BS
- In reinforced and non-reinforced and cracked and non-cracked concrete C20/25 to C50/60
Tensile capacity in concrete hollow body ceilings, (∅6 - ∅10) - expert report no. 21641 - 2016
Fire resistance rating when exposed to fire according to the uniform temperature time curve in masonry (Mz, KSL, KS), and reinforced concrete, (∅6) - expert report no. 2101/173/18 - 2018
Fixing point with approval (∅6 - ∅10):
In normal weight concrete C20/25 to C50/60 (cracked and non-cracked concrete)
Anchors in a redundant non-structural system, with approval:
- In normal weight concrete C20/25 to C50/60 (cracked and non-cracked concrete, (∅6))
- In hollow-core prestressed concrete ceilings C30/37 - C50/60, (∅6)
Specifically designed for surface-flush, visually appealing mounting
Suitable for fastening medium to heavy loads in concrete:
- Attachment of e.g. staircase railings and balcony balustrades, handrails, steel constructions, wooden substructures, metal profiles etc. in in-place installation
- Fastenings under seismic conditions in earthquake areas
- Fastenings under exposure to fire
W-BS/A4 (stainless steel A4) can be used in dry indoor conditions, outdoors (including in industrial atmospheres and coastal areas) or in wet rooms, provided that no particularly aggressive conditions are present
For use in concrete < C20/25 and pressure-resistant natural stone (without approval)
Select RAL-colour code
!! NOTE: On-screen visualisation of the colour differs from real colour shade!!