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The recent post on heated windscreens reminds me of another item on my to-do list.

Is there any way of justifying polycarbonate side windows to a certifying authority?

This one might be a question for Rod based on his work with ICVs, or perhaps someone who couldn't get glass for a chopped project.

I have an FB Holden sedan project which will be based around a 60's drag strip theme. I know there are more sensible things to build but this one makes me smile. Blown and mechanically injected grey motor, dry sumped, Repco headed, banjo LSD... and engineered/registered (just) in NSW via NCOP. I've been collecting parts for a long time, and am almost there.

I know too that polycarb scratches, can be crap to see out of if warped, is hard to cut in an emergency etc. Bear with me... I want light weight windows, and have a fancy for green-tinted polycarbonate. I would settle for just side windows, but a rear screen too would be good. Suspect there is no chance at all of a clear polycarbonate windscreen. My engineer is relatively fussy, but open to an argument when I can demonstrate that code is met (as an example, I can demonstrate that fibreglass doors are OK on the same vehicle ... and have the moulds to make them).

My understanding of NCOP is that it does not prohibit polycarbonate for a modified FB Holden, but instead refers to "transparent material". The "transparent material" has to comply with one of:
 Australian Standard AS R1-1965 Safety Glass for Land Transport;
 Australian Standard AS R1-1968 Safety Glass for Land Transport;
 Australian Standard AS 2080-1977 Safety Glass for Vehicles;
 British Standard BS 857:1967 Specification for Safety Glass for Land Transport;
 British Standard BS 5282:1975 Road Vehicle Safety Glass;
 British Standard BS AU178:1980 Road Vehicle Safety Glass;
 Japanese Industrial Standard JIS R 3211-1979 Safety Glasses for Road Vehicles; and
 American National Standard ANSI Z26.1-1980 Safety Code for Safety Glazing Materials
for Glazing Motor Vehicles Operating on Land Highway.

These standards all refer to glass... except the last one. I started digging into it, and got the impression that some plastics can be acceptable. I've since misplaced my notes. Before I go and rework that ANSI standard, has anyone done this work before me?

Cheers,
Harv

My first car which was a MG TD had polycarbonate like side curtains on the doors. I don't know if they were poly carbonate but were a similar material. They were called perspex ????

Perspex is similar (clear, tough plastic) but not as tough as polycarbonate. Perpex is a trade name of poly methyl methyacrylate, sometimes known as Plexiglass. It shatters or snaps into hard edges under load. Polycarbonate, often called by the trade name of Lexan, is a lot tougher.

When I was younger, Dad made some headlight covers for me from Lexan. I asked him if they were tough enough to handle rocks (rural upbringing ). Never forget him turning around and swinging at them with a socket breaker bar. Didn't even mark them.

Cheers,
Harv

It's my understanding that a windshield is specified as safety glass, whereas the rest of the ADRs talk to "if glass is used, it must be safety glass"...

Hi Harv

It appears that not all windows need to be approved glass or even glass -

https://www.etsy.com/au/listing/1279341 ... gJCGvD_BwE

In the good old days - How do you convert a Datsun 1600 into a rally car ? Start with a 44 gallon drum and when it is full you are nearly there !

Are there any Ford GT40s in Oz? They have Lexan side windows are are street legal here

Found some of my old notes. Please bear with me if the info below gets techo. The vehicle I am thinking of building is unusual (not your average 350 Chev into a Commodore), and in some cases pushes the rules. It will be built with the spirit of Smokey Yunick in mind:

“You don't race cars, you race the rule book.”

I need to be sure that what I build is safe, and that you and I are both covered by insurance if something goes wrong.

NCOP Section LZ Appendices Appendix G Safety Glazing Material and Applied Window Tinting Section 5 Approved Material for Windscreens, Windows and other glazing allows:

For vehicles manufactured after June 1953 transparent material used in the windscreen, window, or interior partition of a motor vehicle must be of an approved material. Replacement transparent material must also be of an approved material.

Approved material is then defined as complying to a list of standards, which all have "glass" in their title (no use to me as I want to use plastic), except American National Standard ANSI Z26.1-1980 Safety Code for Safety Glazing Materials for Glazing Motor Vehicles Operating on Land Highway.

I only have a draft copy of ANSI Z26.1 (https://www.citsa.com.mx/images/Normas/Z-26.pdf), so the info below may not be fully correct.

ANSI Z26.1 defines a number of applications/locations/uses for glazing materials. The two applications that are of interest to me are:

Item 1. Safety Glazing Material for Use Anywhere in Motor Vehicle
There is a conflict in my draft copy, as Section 4.1 Item 1 indicates I can use "multiple glazed units" (two bits of glazing separated by an air gap), or "other than multiple glazed units" i.e. no limit on what material I could use. Table 1, which outlines the tests required, only allows for multiple glazed units and laminated glass i.e. not plastic. So I may not be able to have a plastic windshield. I can live with that.

Item 2. Safety Glazing Material for Use Anywhere in Motor Vehicle Except Windshields.
This is clearer, and Table 1 allows for rigid plastics. The material would need to pass the following tests:
1 Light Stability
2 Luminous Transmittance
3 Humidity test
4 High temperature
7 Impact, plastic, ball drop
9 Impact, variable temperature
11 Simulated weathering
12 abrasian resistance interior
13 abrasian resistance exterior
14 chemical resistance, non stressed
15 chemical resistance, stressed
16 dimensional stability
18 flammability < 1.27mm
19 flammability > 1.27mm

This may be a possibility... I just need to find someone who can demonstrate (or certify) that their plastic meets those tests. Some Googling shows that GAT Technologies in Victoria may be the company I need, and that their Rencraft material may already be certified.
https://gat.com.au/rencraft/

Suspect they won't have Rencraft in the green tint I am dreaming of (60's dragstrip flavour), but I'll give them a call Monday and see how I go.

Cheers,
Harv

If I was trying to Engineer those windows I would pose a question; I have a 1960 MG A (Could be a Mk I Sprite, Triumph TR# or a bunch of other Pommie cars) that needs new side curtains. All of those had Perspex sliding windows.

Surely you can't be expected to replace them with glass and if it's good enough for those vehicles then i should be good enough for a similar aged vehicle.

I'd talk to your Engineer now and if he says no, start working on a good argument as to why he should change his mind.

Option 2, is get it registered with glass and retrofit poly.

Insurance doesn't enter into it. For an insurer to deny a claim they have to prove the Proximate Cause of the accident/event was the poly window/s. Pretty hard to see how that would happen unless they were so scratched you couldn't see out of them.

To save anyone looking up Proximate Couse it is - The active efficient means that sets in motion a chain of events that brings about a result without the intervention of a new or independent force.

35 years in Insurance taught me something!

I'm working Option 1: Convince the engineer. He is not too bad, but can be pedantic.

A good example would be seatbelts on my wagon. Many engineers would look at them, eyeball the distances between mounting points and approve. I had to demonstrate that I met NCOP... lots of measurements, PVC tape to mark stuff onto the side walls of the car, and photos.

Similar with maximum engine capacity. In theory I could get within 1.5% of running a 350ci engine (based on original engine and weight), but instead had to run a 327 to comply. To his credit he recognised NCOP will allow almost any engine I wanted, but would need to pass a beam test. I chickened out at that point and went with the 327, as the beam test was very hefty in price.

Cheers,
Harv

Beam test can be done at home and if it works you can then do a formal test.

Quite a few clubs (such as Ausclubbies) have their own equipment.

The ASRF TAC will not accept anything but Toughened glass or laminated Glass in Qld as I have tried them on it ,I have spoken to engineers here too and its no go there either ,so Dont like your chances ,maybe different in other states