Georgian Wired Glass

[RON G]

Following a fire risk assessment in one of our hospitals the assessor said that we should check the glazing in all the fire doors and associated frames, this glazing is geogian wired and has been in situ for approx 30 years, we therefore asked a local glazing company to carry out a survey and they stated that the georgian wired glass is not up to modern standards and should be replaced (103 panes) my question is should this glazing be replaced or as it was accepted in the past by the Fire Service and local Building inspectorate should we retain the original glazing.

Hope you can help.

[wee brian]

Who accepted it in the past is irrelevant.

If its still safe enough then that's OK  - if its unsafe then change it.

Whilst modern standrads chagne fires a re still orangey red things that get hot.

[jayjay]

I would be interested in the reasons why 30 year old glass needs replacing.
Providing the securing of the glass within the frames is satisfactory I can not see why it should have chaged over time.

Depending on the resons and what the fire resisting doors are separating I think it would be reasonable for any aged wired glass or even the old copper framed glass to provide smoke separation (along with smoke seals).

I would be asking for the assessors reasoning and technical guidance.

[kurnal]

Lots of buildings have old style fire resisting glazing with inadequate beadings, inadequate timber glazing bars, no proper glazing systems, etc.
Whether they need replacing depends on condition, location and purpose. In short apply a risk assessment.

If its glazing to a low risk area or for a patient area that will be evacuated horizontally and fairly quickly- maybe no problem, but if used for compartmentation, staircases serving wards it should be replaced.

[redbadge]

Wired glass in itself should not be a problem, the wires hold the glass together after the panes crack under test.

More importantly, as Kurnal states, the frame material and density, the method of retaining the glass - bead material - shape / profile and fixing method, plus the glazing system between bead and glass, are all critical items.

I have a lot of test data available from which an informed judgement can be made if the above information can be established. Would also need to know the panel dimensions and performance required.

[jokar]

Aren't there 2 differing types of georgian wired glass, one that is inherently fire resistant and one style that is not, perhaps the glass and glazing federation can offer some advice.

[redbadge]

Here we go...

There are at least 2 UK based wired glass producers, but as Pilkington have the dominant market share I'll focus purely on their products:

They market 4 types of wired glass-

Pyroshield clear
Pyroshield texture
Pyroshield safety clear
Pyroshield safety texture

The test data held by Pilkington offers 60 minute fire performance for all of these (Integrity only, no insulation.)

Further producers (such as me) take the product and then re-test it based on what we want to achieve in order that we are able to broaden our product offer, for example 120 & 240 minute performance have been proven - but that evidence is owned by the companies that paid for the test.

[wee brian]

http://www.ggf.co.uk/learn/view_doc_members_info_postings.phtml?id=26

[redbadge]

Nice one Brian!

http://www.ggf.co.uk/learn/view_doc_members_info_postings.phtml?id=26

[BCO]

Ron, you say the local glazing company said its not up to the current standard. Did they qualify that they were referring to fire resistance? Could it be that they were referring to standards in relation to part N of the Building Regulation (safety glass requirements).

At the time part N was introduced (in the 90s), the standard Georgian wired glass did not comply with the requirements in terms of safe breaking or robustness.  To comply with part N, manufactures changed their product. The change concerned the gauge of the wire within the glass, it had to be thicker to comply with the requirements of part N. so old Georgian wire glass has thin wires and does not comply with part N and modern Georgian wire glass has thicker wires and does comply.  Both old and new meet the requirements in terms of fire resistance (subject to its installation method)

Therefore, if this is the case, it may not be necessary to change the glazing. Or at least not for the purposes of fire safety!

[RON G]

Thanks to everyone for their input, BCO, I think you have hit the nail on the head, the glazing company did say that the gauge of the wire was incorrect, however they didnt mention the reason for this, maybe they didnt know!!!

Thanks

RonG

[kurnal]

Fire-resistant glazed systems specifications for use in a vertical orientation are fairly easily found.

However in a historic building I need to find a fire resisting glazing system to replace existing roof lights which are adjacent to an external escape. These have never been protected in the past- I need to find a sympathetic and cost effective way of upgrading them to a half hour standard in respect of integrity.

The pitch of the roof is 30 degrees and the total area of the roof lights is 2m wide and 1.4m high. I am hoping to specify georgian wired as potentially the cheapest solution

Please does anyone know of any publicly available specifications for tested and approved  timber based fire resisting glazing systems suitable for use in an inclined plane in keeping with a Victorian grade 1 listed building?

[wee brian]

Unlikely you'll find much - gravity and gooey glass dont mix well.