# iSteel --- ## Pages - [GGF Guidelines](https://www.isteel.co.uk/ggf-guidelines/): Glass Scratches & Visual Imperfections guidelines, we have provided a summary of the inspection criteria and acceptable tolerances. --- ## Posts - [Domestic, Hertfordshire](https://www.isteel.co.uk/projects/domestic/domestic-hertfordshire/): iSteel client chose a double door arrangement with fixed glazed side panels to form a new entrance between the hall and lounge. - [Domestic, Leicestershire](https://www.isteel.co.uk/projects/external/domestic-leicestershire/): iSteel external ‘FineLine’ products are thermally broken steel, fabricated by hand in Yorkshire and utilising either double or triple glazed glass. - [Domestic, Altrincham](https://www.isteel.co.uk/projects/external/domestic-altrincham/): Having a clear vision of the design, the client struggled finding the right supplier that could offer him the design in thermally broken glazed steel. - [Commercial, Hull](https://www.isteel.co.uk/projects/external/commercial-client-hull/): An historic building in a city centre can be a renovation challenge, also a responsibility to modernise whilst maintaining the architecture. - [Domestic, Harrogate](https://www.isteel.co.uk/projects/domestic/domestic-client-harrogate-2/): iSteel was appointed to design, supply and install an E30 fire rated solution for a domestic client in Teddington. - [Domestic, Sheffield](https://www.isteel.co.uk/projects/external/domestic-client-sheffield-2/): iSteel was appointed to design, supply and install our SL70 Thermally Broken Steel System for a client in Sheffield. - [Harold Newsome, Leeds](https://www.isteel.co.uk/projects/fire-rated/harold-newsome-leeds/): iSteel was appointed by our client in Macclesfield, to design, supply and install our single glazed system. - [Domestic, Nottinghamshire](https://www.isteel.co.uk/projects/domestic/domestic-client-nottinghamshire/): iSteel was appointed to design, supply and install our SL70 Thermally Broken Steel System for a client in Nottinghamshire. --- # # Detailed Content ## Pages > Glass Scratches & Visual Imperfections guidelines, we have provided a summary of the inspection criteria and acceptable tolerances. - Published: 2025-04-25 - Modified: 2025-04-28 - URL: https://www.isteel.co.uk/ggf-guidelines/ GGF Guidelines Glass Scratches & Visual ImperfectionsThe Glass and Glazing Federation (GGF) sets out industry standards for acceptable visual quality in flat transparent glass (including float, laminated, toughened, and coated glass). Below is a summary of the inspection criteria and acceptable tolerances:Inspection Conditions Glass should be inspected in natural daylight, not direct sunlight. Glass must be clean and dry. View from a minimum distance of 3 meters for toughened/laminated/coated glass. Inspect from three angles: straight on, and 45° from both the left and right. A 50mm wide band around the edge is excluded from inspection. Acceptable Imperfections Fine scratches up to 25mm long (provided they are not grouped or visually obtrusive). Minute embedded particles. Small air bubbles or blisters. Unacceptable Defects Bunched or noticeable imperfections that distract visually. Smears, fingerprints, or dirt on either glass face. Contaminants or marks inside sealed units. Special Considerations Toughened Glass: May show natural phenomena like haze, bowing, or anisotropy. These are not considered defects. Laminated Glass: Due to its layered structure, more imperfections may be visible. A 25% greater tolerance is allowed compared to standard float glass. Inspection Conditions Glass should be inspected in natural daylight, not direct sunlight. Glass must be clean and dry. View from a minimum distance of 3 meters for toughened/laminated/coated glass. Inspect from three angles: straight on, and 45° from both the left and right. A 50mm wide band around the edge is excluded from inspection. Acceptable Imperfections Fine scratches up to 25mm long (provided they are not grouped... --- --- ## Posts > iSteel client chose a double door arrangement with fixed glazed side panels to form a new entrance between the hall and lounge. - Published: 2022-12-02 - Modified: 2024-07-30 - URL: https://www.isteel.co.uk/projects/domestic/domestic-hertfordshire/ - Categories: Domestic, Double Doors with Side Panels @ET-DC@eyJkeW5hbWljIjp0cnVlLCJjb250ZW50IjoicG9zdF9kYXRlIiwic2V0dGluZ3MiOnsiYmVmb3JlIjoiIiwiYWZ0ZXIiOiIiLCJkYXRlX2Zvcm1hdCI6ImRlZmF1bHQiLCJjdXN0b21fZGF0ZV9mb3JtYXQiOiIifX0=@Hertfordshire based client chose a double door arrangement with fixed glazed side panels to form a new entrance between the hall and lounge. The Glazing has achieved the desired effect of an open, light and airy space but also allows the space to be closed off to retain heat and dampen sound when required. The simple design details with minimal cross bars in RAL7016 Textured Anthracite looks stunning. iSteel SLIM Single Glazed, Internal Swing Opening Double Doors and fixed side panels Single Glazed 6mm Clear Toughened Safety Glass RAL7016 Textured Anthracite ‘Classic’ Lever Latch Handles & Lock Feel free to contact us and we will get back to you with a bespoke quote. Follow us on:facebookinstagramlinkedin --- > iSteel external ‘FineLine’ products are thermally broken steel, fabricated by hand in Yorkshire and utilising either double or triple glazed glass. - Published: 2022-07-25 - Modified: 2025-01-31 - URL: https://www.isteel.co.uk/projects/external/domestic-leicestershire/ - Categories: Double Doors with Side Panels, Arched Doors, External @ET-DC@eyJkeW5hbWljIjp0cnVlLCJjb250ZW50IjoicG9zdF9kYXRlIiwic2V0dGluZ3MiOnsiYmVmb3JlIjoiIiwiYWZ0ZXIiOiIiLCJkYXRlX2Zvcm1hdCI6ImRlZmF1bHQiLCJjdXN0b21fZGF0ZV9mb3JtYXQiOiIifX0=@The Coach House. Our client was undertaking a challenging project, converting a former coach house into a habitable dwelling. Being grade two listed, there were a lot of planning and historic England stipulations for planning consent. One of the conditions were that modern doors replacing timber must be made of steel and reflect the design of the original heritage glazed steel windows. iSteel received the architects instruction after exhausting other avenues because we were the only company which would take on the intricate arched doors with sunrise splay and not only install but also design and fabricate making the process smooth and simple. iSteel external ‘FineLine’ products are thermally broken steel, fabricated by hand in Yorkshire and utilising either double or triple glazed glass. iSteel FineLine, External Window and Door System Thermally Broken Steel frame Double Glazed 28mm Argon Filled, Double Glazed units. U-Value 1. 2 RAL9005 Textured Black Swing Opening 180 degree hinges Lever Latch, locking handles with lock box detail Designed, Surveyed, Fabricated, and Installed by iSteel Feel free to contact us and we will get back to you with a bespoke quote. Follow us on:facebookinstagramlinkedin --- > Having a clear vision of the design, the client struggled finding the right supplier that could offer him the design in thermally broken glazed steel. - Published: 2022-07-01 - Modified: 2024-09-23 - URL: https://www.isteel.co.uk/projects/external/domestic-altrincham/ - Categories: Double Doors with Side Panels, External @ET-DC@eyJkeW5hbWljIjp0cnVlLCJjb250ZW50IjoicG9zdF9kYXRlIiwic2V0dGluZ3MiOnsiYmVmb3JlIjoiIiwiYWZ0ZXIiOiIiLCJkYXRlX2Zvcm1hdCI6ImRlZmF1bHQiLCJjdXN0b21fZGF0ZV9mb3JtYXQiOiIifX0=@Extra Ordinary External Doors! Altrincham based client undertaking a home renovation including a kitchen extension and balcony, required thermally broken doors to both the master bedroom and kitchen diner. Having a clear vision of the design, the client struggled finding the right supplier that could offer him the design in thermally broken glazed steel. iSteel design, fabricate and install all from our HQ in Yorkshire, which allows us to be adaptable to design requirements and we only produce thermally broken external glazed steel products making us a market leader. Looks like its going to be a fantastic home! iSteel FineLine, External Window and Door System Thermally Broken Steel frame Double Glazed 28mm Argon Filled, Double Glazed units. U-Value 1. 2 RAL9005 Textured Black Swing Opening 180 degree hinges Lever Latch, locking handles with lock box detail Designed, Surveyed, Fabricated, and Installed by iSteel Feel free to contact us and we will get back to you with a bespoke quote. Follow us on:facebookinstagramlinkedin --- > An historic building in a city centre can be a renovation challenge, also a responsibility to modernise whilst maintaining the architecture. - Published: 2021-08-12 - Modified: 2025-01-31 - URL: https://www.isteel.co.uk/projects/external/commercial-client-hull/ - Categories: Commercial, Arched Doors, External @ET-DC@eyJkeW5hbWljIjp0cnVlLCJjb250ZW50IjoicG9zdF9kYXRlIiwic2V0dGluZ3MiOnsiYmVmb3JlIjoiIiwiYWZ0ZXIiOiIiLCJkYXRlX2Zvcm1hdCI6ImRlZmF1bHQiLCJjdXN0b21fZGF0ZV9mb3JtYXQiOiIifX0=@An historic building in a city centre can be a renovation challenge, but also a responsibility to modernise whilst maintaining the period integrity of the architecture. Our Hull based client approached us to design, manufacture and install heritage style arched steel performance doors which would look the part but also offer protection from the Humber Estuary elements. iSteel External Glazed doors are thermally broken achieving a U-value of 1. 5 with double glazed, Argon filled, low E glass with a U-value of 1. 2. SL70 Thermally Broken Steel External Door System Colour RAL9005 Textured Black Lever Latch Lock Handle 6mm Toughened Double Glazed, Argon Filled glass with integra spacer bars Feel free to contact us and we will get back to you with a bespoke quote. Follow us on:facebookinstagramlinkedin --- > iSteel was appointed to design, supply and install an E30 fire rated solution for a domestic client in Teddington. - Published: 2021-07-13 - Modified: 2025-01-31 - URL: https://www.isteel.co.uk/projects/domestic/domestic-client-harrogate-2/ - Categories: Domestic, Arched Doors, External @ET-DC@eyJkeW5hbWljIjp0cnVlLCJjb250ZW50IjoicG9zdF9kYXRlIiwic2V0dGluZ3MiOnsiYmVmb3JlIjoiIiwiYWZ0ZXIiOiIiLCJkYXRlX2Zvcm1hdCI6ImRlZmF1bHQiLCJjdXN0b21fZGF0ZV9mb3JtYXQiOiIifX0=@Harrogate based client wanted to create an air trap between the exposed porch and existing front door by introducing external thermally broken double glazed steel doors, whilst respecting the character of the property. The unusual shape at the head of the door was thought to be a challenge but our very talented fabricators had no problem making the final product look effortless. iSteel are always delighted to take on a challenge and love to see the stunning finished results. SL70 Steel, Double Glazed System 28mm DG unit with integral back-to-back spacer bars. RAL9005 Textured Black Powder coat finish. Steel external Grade Double Doors. Face applied 25 x 3. 5mm Flat bar profile. Feel free to contact us and we will get back to you with a bespoke quote. Follow us on:facebookinstagramlinkedin --- > iSteel was appointed to design, supply and install our SL70 Thermally Broken Steel System for a client in Sheffield. - Published: 2021-04-12 - Modified: 2024-09-23 - URL: https://www.isteel.co.uk/projects/external/domestic-client-sheffield-2/ - Categories: External @ET-DC@eyJkeW5hbWljIjp0cnVlLCJjb250ZW50IjoicG9zdF9kYXRlIiwic2V0dGluZ3MiOnsiYmVmb3JlIjoiIiwiYWZ0ZXIiOiIiLCJkYXRlX2Zvcm1hdCI6ImRlZmF1bHQiLCJjdXN0b21fZGF0ZV9mb3JtYXQiOiIifX0=@iSteel was appointed to design, supply and install our SL70 Thermally Broken Steel System for a client in Sheffield. The clients requirement was for a modern twist on the industrial look windows and doors – sleek profiles but with the modern performance attributes for thermal and acoustic properties. SL70 Steel, Double Glazed System 28mm DG Units with integral back to back black spacers bars Lever handles, powder coat finished to match system on iSteel back box RAL9005 Black Textured Finish Doors with Fan and Sidelights Face applied 25mm X 3. 5mm flat bar profile over integra spacers bars for ultra slim transom detail Feel free to contact us and we will get back to you with a bespoke quote. Follow us on:facebookinstagramlinkedin --- > iSteel was appointed by our client in Macclesfield, to design, supply and install our single glazed system. - Published: 2020-09-29 - Modified: 2024-09-23 - URL: https://www.isteel.co.uk/projects/fire-rated/harold-newsome-leeds/ - Categories: Commercial, External, Fire Rated @ET-DC@eyJkeW5hbWljIjp0cnVlLCJjb250ZW50IjoicG9zdF9kYXRlIiwic2V0dGluZ3MiOnsiYmVmb3JlIjoiIiwiYWZ0ZXIiOiIiLCJkYXRlX2Zvcm1hdCI6ImRlZmF1bHQiLCJjdXN0b21fZGF0ZV9mb3JtYXQiOiIifX0=@iSteel was appointed by Harold Newsome Ltd to design, supply and install various glazed solutions throughout their new head office in Leeds. Harold Newsome Ltd was established in March 1937, for nearly 80 years they have been an industry leader and innovator in the field of structural steel design, fabrication and installation. The company has grown rapidly in the last decade, whilst contracts have increased in scope and complexity the core values at the heart of this family run company have remained. This allows the business to provide a personal touch alongside the professionalism and attention to detail which they afford every project. External Entrance & Full Height Boardroom Window iSteel SL38 Aluminium, Double Glazed System Thermally Broken 28mm Double Glazed Units with Integra Bars to Suit Transom/Mullion Requirement RAL9005 Face Applied Industrial Bars Fully supplied and installed Feel free to contact us and we will get back to you with a bespoke quote. Follow us on:facebookinstagramlinkedin --- > iSteel was appointed to design, supply and install our SL70 Thermally Broken Steel System for a client in Nottinghamshire. - Published: 2020-06-17 - Modified: 2024-09-23 - URL: https://www.isteel.co.uk/projects/domestic/domestic-client-nottinghamshire/ - Categories: Domestic, External @ET-DC@eyJkeW5hbWljIjp0cnVlLCJjb250ZW50IjoicG9zdF9kYXRlIiwic2V0dGluZ3MiOnsiYmVmb3JlIjoiIiwiYWZ0ZXIiOiIiLCJkYXRlX2Zvcm1hdCI6ImRlZmF1bHQiLCJjdXN0b21fZGF0ZV9mb3JtYXQiOiIifX0=@iSteel was appointed to design, supply and install our SL70 Thermally Broken Steel System for a client in Nottinghamshire. The clients requirement was for a modern twist on the industrial look windows and doors – sleek profiles but with the modern performance attributes for thermal and acoustic properties. SL70fa Steel, Double Glazed System 28mm DG Units with integral back to back black spacers bars Customers own choice of lever handles, powder coat finished to match system on iSteel back box RAL9005 Black Textured Finish Full Height Doors Face applied 25mm X 3. 5mm flat bar profile over integra spacers bars for ultra slim transom detail Feel free to contact us and we will get back to you with a bespoke quote. Follow us on:facebookinstagramlinkedin --- ---