{"id":3693,"date":"2026-10-16T07:30:59","date_gmt":"2026-10-16T07:30:59","guid":{"rendered":"https:\/\/duronupvc.com\/blog\/?p=3693"},"modified":"2026-10-16T07:30:59","modified_gmt":"2026-10-16T07:30:59","slug":"upvc-casement-window-technical-specifications","status":"publish","type":"post","link":"https:\/\/duronupvc.com\/blog\/upvc-casement-window-technical-specifications\/","title":{"rendered":"uPVC Casement Window Specifications: Features, Sizes & Benefits"},"content":{"rendered":"

Specifying a uPVC casement window goes beyond choosing the colour and the size. The uPVC casement window specification that actually determines how the window performs \u2014 how it seals, how it handles weather, how long the hardware lasts \u2014 sits in the profile series, the chamber design, the hardware selection, and the glazing configuration. These aren’t details that show up in a showroom brochure, but they’re the details that separate a window that works quietly for 20 years from one that needs repair in three.<\/span><\/p>\n

Most buyers discover these specifications only after they’ve experienced a problem \u2014 a window that whistles in wind, hardware that corrodes, or a corner joint that starts to open. The better approach is to understand the uPVC casement window specification before installation.<\/span><\/p>\n

Duron uPVC manufactures profiles used across India for casement window fabrication. Their 60-series profile systems are engineered for Indian climate conditions with the hardware compatibility and dimensional standards that fabricators need for consistent results. This guide covers the full specification.<\/span><\/p>\n

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uPVC Casement Window Specifications<\/b><\/h2>\n

A complete uPVC casement window specification covers the following parameters:<\/span><\/p>\n

Profile series:<\/b> The frame and sash profile depth \u2014 typically 60mm, 70mm, or 80mm.<\/span><\/p>\n

Chamber design:<\/b> Single, multi, or reinforced chamber construction.<\/span><\/p>\n

Wall thickness:<\/b> The minimum thickness of each profile wall in millimetres.<\/span><\/p>\n

Hardware:<\/b> Hinge type, locking mechanism, handle, and operating hardware.<\/span><\/p>\n

Glazing:<\/b> Glass type, thickness, and the glazing bead system holding it in place.<\/span><\/p>\n

Sealing:<\/b> Gasket type and placement for weather and acoustic performance.<\/span><\/p>\n

Corner joints:<\/b> Method of frame and sash corner connection.<\/span><\/p>\n

Understanding each of these parameters is what makes a uPVC casement window specification meaningful rather than superficial.<\/span><\/p>\n

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Key Components of uPVC Casement Windows<\/b><\/h2>\n

Profile System<\/b><\/h3>\n

The 60 series uPVC profile is the most widely used standard for residential casement windows in India \u2014 a 60mm frame depth that provides adequate rigidity for standard window spans without excessive material cost. Larger spans or heavier glazing units typically require 70mm or 80mm profiles.<\/span><\/p>\n

Multi-chamber uPVC profile design<\/a> is the primary structural differentiator. A multi-chamber profile design creates air pockets between chamber walls that resist thermal bridging and improve rigidity compared to single-chamber profiles. Better profiles have 3\u20135 internal chambers across the frame section.<\/span><\/p>\n

Profile wall thickness mm is specified in the design standard. European Norm (EN12608) specifies minimum wall thicknesses for uPVC profiles by impact class. The main walls of a quality profile<\/a> should be minimum 2.8mm thick \u2014 thinner walls reduce rigidity and long-term dimensional stability.<\/span><\/p>\n

uPVC Window Steel Reinforcement<\/b><\/h3>\n

All load-bearing sections of a casement frame \u2014 particularly the frame header and sill, and the sash section opposite the hinge \u2014 should have uPVC window steel reinforcement. A galvanised steel insert is fitted inside the profile cavity, typically 1.5mm\u20132mm thick.<\/span><\/p>\n

Steel reinforcement prevents the frame from deflecting under the window’s own weight and under wind load. For casement windows above 900mm in width, reinforcement is critical. Without it, the sash will sag at the hinge-side corner, causing alignment problems and seal failure over time.<\/span><\/p>\n

EPDM Gasket Window Sealing<\/b><\/h3>\n

The EPDM gasket window seal runs around the perimeter of the sash where it contacts the frame. EPDM maintains flexibility across India’s temperature range \u2014 from sub-zero temperatures in North India winters to 45\u00b0C+ summer heat \u2014 without hardening or cracking. PVC gaskets harden over time and lose their seal; EPDM gaskets don’t.<\/span><\/p>\n

A double gasket arrangement \u2014 one on the frame, one on the sash \u2014 provides better weather exclusion than a single gasket system and is the standard in quality casement window specification.<\/span><\/p>\n

Glazing Bead uPVC<\/b><\/h3>\n

Glazing Bead uPVC System Locks the Glass Unit into the Sash Glazing Bead uPVC systems generally have snap-fit bead profiles that click into the sash rebate, once the glass unit is installed. A good glazing bead uPVC system will hold the glass on all four sides with uniform clamping force. An inferior bead design will allow the glass to move in the rebate, putting pressure on the silicone sealant.<\/span><\/p>\n

Friction Stay Hinges<\/b><\/h3>\n

Outward opening casement windows will be fitted with friction stay hinges as standard. A casement window hinge holds the sash at any point in its open position, as opposed to allowing the sash to hang freely. This gives some control over air flow without needing to use an additional stay arm.<\/span>
\n<\/span>Friction stay hinges come in a range of heavy-duty ratings – often 80kg or 130kg for domestic casement windows. Heavier glazing units including large double-glazed panels will have a higher ratings. An undersized hinge will cause the sash to sag in time and compromise the seal at the same time as affecting the locking position.<\/span><\/p>\n

Espagnolette Locking System<\/b><\/h3>\n

U PVC Casement \u2013 3 Point Locking System Windows will use the three-point locking system known as ‘espagnolette’. This secures the sash to the frame at three points simultaneously; top, bottom, and at the handle position. This is what gives modern uPVC casement windows the weatherproofing and security advantages over single point latches.<\/span><\/p>\n

When the handle is turned, a connecting rod runs the full height of the sash, throwing locking shoots into keeps on the frame at each point. The result is a tight, even compression of the EPDM gasket around the full perimeter \u2014 no flex between locking points.<\/span><\/p>\n

Welded Corner Joint Strength<\/b><\/h3>\n

In uPVC window fabrication, frames and sashes are cut at 45\u00b0 and welded together using heat fusion. Welded corner joint strength in properly fabricated windows means the corner is stronger than the profile itself. Poor welding \u2014 incorrect temperature, insufficient pressure, or contaminated surfaces \u2014 produces weak joints that crack visually and structurally over time.<\/span><\/p>\n

Welded corner joint quality is visible in the neatness of the weld seam (even flash, no gaps) and can be tested by applying pressure to the corner \u2014 quality joints don’t flex.<\/span><\/p>\n

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Standard uPVC Casement Window Sizes and Glass Options<\/b><\/h2>\n

Standard casement window sizes for residential use:<\/span><\/p>\n