<h2>V2A stainless steel (1.4301)</h2><p>Contrary to conventional wisdom, even stainless steel can corrode. Base metals (e.g. in dust or chip form) on stainless steel surfaces cause contact corrosion and form “rust spots”. Regular cleaning must be ensured when in contact with de-icing salt. AISI no 1.4301 (V2A) is used for our stainless steel edges and gratings as standard. Stainless steel gratings made of AISI no 1.4404 (V4A) can also be supplied for an additional charge.</p><p> </p><h2>Galvanised steel</h2><p>Steel parts in the channel systems are coated in a protective zinc coating. To ensure permanent corrosion protection, this layer must be protected against mechanical damage and chemical attacks. Contact with calcium-rich or cementitious substances (screed, etc.) can destroy or dissolve the protective zinc coating. Condensed water also attacks the protective layer to form white rust (corrosion of the zinc coating) – this is not a defect. Edges of galvanised channel bodies and covers that are cut on site must be treated with a suitable corrosion protection agent</p><p><strong>PLEASE NOTE:</strong> Galvanised channel elements must not be laid on fresh lime or cement mortar and not grouted with acetic silicone in order to prevent increased corrosion.</p><p> </p>

<h2>Top element</h2><p>The top element acts as additional point drainage for terraces and roof terraces. It also enables easy access to inspect or clean the roof drains. The height of the top can be adjusted even after installation. Available with an MW 30/10 mesh grating</p>

<h2>Branch channel</h2><p>A branch channel ensures rapid drainage from the channel to the outlet. The perforation allows additional water to be drawn from the adjoining surface and conducted directly to the outlet.</p>

<h2>Gravel stop strip<strong> </strong></h2><p>The gravel stop strip creates a border between BG-FLEX façade channels and the adjoining gravel surface. The perfectly coordinated height of the element allows the gravel stop strip to be used with BG-FLEX FA as well as BG-FLEX FA plus. The aluminium design ensures an even longer service life.</p>

<p><strong>Distinguishing between three application situations</strong>:</p><p> </p><ul><li>Unprotected situation: Wall, door or window connection that is exposed to direct weathering by driving rain</li><li>Partially protected situation: Wall, door or window connection that is partially exposed to weathering by driving rain</li><li>Protected situation: Wall, door or window connection that is always protected from weathering by driving rain</li></ul>

<h2>Connections of door and window elements in line with Austrian Standard B 3691:</h2><p> </p><figure class="table"><table><tbody><tr><td> </td><td>Min. width of the drainage channel</td><td>Min. height of the drainage channel in mm</td><td>Min. height above covering</td><td>Recommended product</td></tr><tr><td rowspan="2">Partially protected situation</td><td>120 mm (4.7″)</td><td>80</td><td>10</td><td>FA RB 130, fixed element height 80 FA RB 130, variable element height 80-120</td></tr><tr><td>200 mm (7.9″)</td><td>40</td><td>10</td><td>FA RB 200, fixed element height 50 BG-FA RB 200, variable element height 50-70</td></tr><tr><td rowspan="2">Unprotected situation</td><td>120 mm (4.7″)</td><td>180</td><td>10</td><td>FA RB 130, fixed element height 180</td></tr><tr><td>200 mm (7.9″)</td><td>90</td><td>10</td><td>FA RB 200, fixed element height 90 FA RB 200, variable element height 70-100</td></tr></tbody></table></figure>

<h2>Other important requirements in Austrian Standard B 3691:2019</h2><p> </p><ul><li>The hydraulic cross-section of the channel must be adapted to the local conditions</li><li>Branch channels for roof drainage must be planned under surfaces in gravel beds or under bound surfaces</li><li>Perforated or closed side walls of the drainage channel</li><li>The height of drainage channels with variable element height should be able to be adjusted when installed</li><li>If façade channels are installed in front of the soffit, the surface between the door element and the channel must be inclined by 5°. In this case, the channel must protrude beyond the width of the door reveal by at least 20 cm.</li></ul>