Packer’s are important to install windows professionally, as they are designed in cooperation with window manufacturers often for the specific window profile to work safely over its guaranteed period.

The design, hardness and compatibility of packers is key to performance of their designed role. The construction of the packer and it’s compatibility with the rest of the frame materials is important that is why our materials are tested and developed with window system designers and are manufactured from prime materials, to exacting hardness and dimensional tolerances.

Location is also key and they should be used a minimum of 30mm from the frame cormers.

But what does the packer do?

As support blocks they carry the load of the glazed unit and spread that into the base frame profile.

As location blocks they ensure the glazed unit is plumb and square to the frame and are used in certain window types as support blocks to hinge and locking points.

They increase security around fixing points to prevent the deflection of the frame extrusion. Packers are designed to work with Bridge packers to maintain drainage and ventilation in the window frame rebate.

Packers are also used to Toe and heel glazed units, doors, bi fold and patio door sets.

Standard BS 8000: Part 7:1990 requires the following.

Section3 – Glazing techniques
3.1.2 Setting blocks
b)  Width

The width is to be equal to either:

1. The thickness of the sheet or unit PLUS back clearance is used with adjacent distance pieces; or
2. The thickness of the sheet or unit ONLY if used with load bearing tapes

3.1.3 Location blocks

Use location blocks only for opening lights or door conditions glazed with glass

Treat the blocks at the head of reversible horizontal pivoted windows as setting blocks

Position as shown in the figure using the following sizes

1. length : minimum length 25 mm
2. Width: equal to the thickness of the sheet or unit plus back clearance, unless
3. Equal to the edge clearance

3.1.4    Distance pieces

Place these to coincide on opposite sides of the sheet or unit, and at bead fixing points. Ideally space them at 300 mm centres and within 50 mm of corners. Avoid placing them to coincide with setting or locating blocks

When distance spacers are supplied incorporated in bedding tape products, use the sizes as follows

1. Length : minimum length 25 mm
2. Width height: to suit the depth of the rebate and the glazing technique.
3. Equal to the actual front and back clearance dimensions between the glazing sheet and the rebate or bead.

It has always been a need for the materials between the glazing channel in the frame and the Insulated Glazed Unit (IGU) to be compatible.

Indeed, in BS 8000 : 7 1990 2.2.2 Compatibility of Materials it sates that “Edge seals of insulating units can be attacked by certain solvents contained in glazing materials” therefore the flat packer when used as a setting or distance block has to be compatible with the IGU edge sealant hot melt.

In BS 6262 -1 : 2005 it states,

“It is important to consider the possibility of interaction between adjacent materials, both in the glazing system and between it and the surrounding area”

Follow the Bostik link who manufacturer of the market leading IGU hot melt (B5000). This report provides a summary of the interaction between these components and highlights in conclusion that

Glazpart packers showed a good level of compatibility from this type testing. Ideally analytical testing should always be carried out to confirm suitability for use. It is expected that following these results the B5000 product and therefore the IGU would have no reduced life expectancy with the use of these packers.