Siting A Pir

[HoofHearted]

This is the third thread i've started this week. let's see if it gets hijacked like the other two did...

I want to put a PIR in my office. This room has 2 windows facing each other on opposite walls. So wherever I site a PIR, it is going to have a window in it's field of view. So my question is quite simple. Will the window cleaner set off a PIR when he is on the outside of the building? Or are modern PIR's cleverer than this?

Ian

[kjd2002]

This is the third thread i've started this week. let's see if it gets hijacked like the other two did...

I want to put a PIR in my office. This room has 2 windows facing each other on opposite walls. So wherever I site a PIR, it is going to have a window in it's field of view. So my question is quite simple. Will the window cleaner set off a PIR when he is on the outside of the building? Or are modern PIR's cleverer than this?

Ian

Infra red cant penetrate glass so you will be alrite. The reason they're not supposed to face the window is because of the potential change of heat through it.

[HoofHearted]

Infra red cant penetrate glass so you will be alrite. The reason they're not supposed to face the window is because of the potential change of heat through it.

Ok, that sounds good. I'll give it try. Thank you.

[james.wilson]

your window cleaner wont be a problem but sunlight might, so be careful because of that.

[Guest anguscanplay]

you could consider a ceiling mounted 360degree sensor or even a dueltech sensor but facing windows isn`t as much of an issue nowadays

Regards

Angus

[arfur mo]

This is the third thread i've started this week. let's see if it gets hijacked like the other two did...

I want to put a PIR in my office. This room has 2 windows facing each other on opposite walls. So wherever I site a PIR, it is going to have a window in it's field of view. So my question is quite simple. Will the window cleaner set off a PIR when he is on the outside of the building? Or are modern PIR's cleverer than this?

Ian

ideal place for coverage is in a corner due to the field angles, but if yo have a window each side say EAST and WEST depents how far away but can you but it in the middle of the SOUTH wall so it looks between not at the windows.

biggest problem if facing windows is the possibility of Sunlight reflecting of shinny surfaces into the detector, and they don't have to be high gloss. high sun activity, fast moving clouds on bright windy days (or you window cleaner on a bright day) can set ordinary cheapy pirs off (so don't make a false economy), and why many would recommend fit a more expensive dual-tec or as Angus suggested a 360 ceiling mount if you can cable neatly to it.

if you go for the Dual-Tec option follow the instructions very carefully how to adjust it properly.

regs

alan

[HoofHearted]

The Windows are on the NE and SW walls. The window walls of the room are a good bit narrower than the solid walls. The door is in the north corner next to the window on the NE wall. So i'm probably going to put the PIR in the south corner opposite the door. The window next to the door is more private and therefore more likely to be broken into.

I was looking at the angles. If I put the the PIR half way along the south east wall, it will be able to see the door and both windows. The south west window gets a lot of sunshine. So I think the west corner is the best place to site it looking at the door and NE window.

Ian

[Alarm Co]

what about direct sunlight on to the lense???????

[arfur mo]

what about direct sunlight on to the lense???????

don't think its external, so can't see how that can occur tbh.

imo unlikely unless he has an all glass roof, window frame will normally obscure the Sun if the pir is at recommended height, and a dual-tec will even more likely be ok. used gto be an issue with car head lamp's comming up the drive etc. but now white light filters are used in most pirs it has reduced the problem.

regs

Alan

The Windows are on the NE and SW walls. The window walls of the room are a good bit narrower than the solid walls. The door is in the north corner next to the window on the NE wall. So i'm probably going to put the PIR in the south corner opposite the door. The window next to the door is more private and therefore more likely to be broken into.

I was looking at the angles. If I put the the PIR half way along the south east wall, it will be able to see the door and both windows. The south west window gets a lot of sunshine. So I think the west corner is the best place to site it looking at the door and NE window.

Ian

Hi Ian,

tbh we would need to see it in person to asses the risks and advise accurately, but from what you say it seems ok to me.

general advice is as long as you can cover the entry points and avoid sunlight and draft source issues, like avoiding positioning near air bricks or above radiators, you will likely be ok.

so read the enclosed makers instructions and i suggest 'suck it and see'.

common sense means keep valuable items well away and if possible out of sight from the windows, if they must remain on show. use security anchor wires to opc's etc. to make it harder, at least then the intruder/s will have to penetrate further into the room, so walk into a protected zone if you have any blind spots.

good luck

regs

alan

[NitroN]

Hi Ian,

1. Should be a corner, PIRs in the middle of a wall reduce effective coverage, yes I know that no one suggested this, but I have seen it to often not to state.

2. It seems that light may be your biggest problem. Many PIRs simply use a lense as a white light filter. I suggest you go one further and either use the Siemens 200 series range PIR which uses a black mirror instead of a fresnel lense with excellent white light immunity or you could use an Optex CX range or similar which has double conductive shielding specifically designed to counter white light false alarms.

There are problably many other technologies by many other manufacturers that are designed to do the same thing. In this specific installation if I was you, I would insure that it was not just a standard detector with a "white light lens coating".

Regards

NitroN