Screen mesh cover or not?

[LANING1]

I have a 5 to 6 inch hatching, I read that the top cuts out 50% of the uv. Would it be better to get stand for his lights and remove the top completely. I don't want him to jump or climb out and get hurt. His basking branch is 6in from the top of the enclosure.

 

[kingofnobbys]

I really detest those screen mesh lids

>> temptation for keepers to simply sit all the lights on top = bad
.... the mesh will shade up to 35% of the UVA and UVB ... see *
>> warm air created inside the viv by the basking globe and /or heatpad and /or CHE is immediately lost to the environment ==> you must use much more wattage (electricity) to attain the desired basking spot, warm zone and cool zone temperatures
>> very hard to produce a stable thermal gradient and microclimate see above.
>> very easy for other pets to get into the viv

I recommend buying a solid plywood lid which has provision made for the basking light and air ventilation.
A solid lid will
>> provide a stable platform from which to hang lights and fittings
>> will insulate the viv from the room environment
>> will force warmed air to circulate ==> less wattage needed to get the same temperatures
>> be other pet proof.

* The amount of UV blocked depends on the geometry of the mesh used in the screen lid , this depends on the mesh pattern , the wire diameter and the aperture see

http://a0.leadongcdn.com/attachment/klijKBpqRijSpjlrinSR7ww7fgzb73p/Woven-Mesh.pdf

Is very simple geometry problem to calculate the open area for PLANE mesh , bit more tricky for twilled mesh pattern , Dutch pattern and twilled Dutch patterns.

No 2 plane mesh blocks 30%
No 3 plane mesh blocks 35%
No 6 plane mesh blocks 38%
No 12 plane mesh blocks 38%
No 16 plane mesh block 44%

 

[AHBD]

They don't block that much. Can you post a pic of the screen ? Some mesh is finer + smaller than others + blocks up to 35 %, others are larger holes + block 15% which is not at all a big deal with a powerful uvb bulb like a MVB. I've raised big healthy dragons with and without screen tops.

 

[kingofnobbys]

They don't block that much. Can you post a pic of the screen ? Some mesh is finer + smaller than others + blocks up to 35 %, others are larger holes + block 15% which is not at all a big deal with a powerful uvb bulb like a MVB. I've raised big healthy dragons with and without screen tops.

I refer to the data provided in the mesh maker's specifications PDF in the above post and www.haverboecker.com specs doc = P-17-E-kg.pdf

measuring it

no 2 and no 3 Plane mesh will be lower. Need to specify the aperture size and wire diameter to calculate the shade factor for the mesh.

 

[AHBD]

That's all great info for something that it is relevant to, but here we are looking at a specific aquarium lid. Is that chart all about aquarium mesh ? Which one of those would fall under that category and what could the average person reading that really get out of it ? We are looking for only one of 2 or possibly 3 types of lid mesh. And since I've raised big healthy dragons with screen for over 20 years then I can tell whether it blocks enough uvb to cause health problems.

Oh, and here is the ratings from the ukuvguide :

https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=3&cad=rja&uact=8&ved=0ahUKEwjQ3YvBvKTVAhWq24MKHTM3CoQQFgg8MAI&url=http%3A%2F%2Fwww.uvguide.co.uk%2Ffluorescenttubemeshtests.htm&usg=AFQjCNEblaL0mKNp5_C2jh6Rckx3w67ucg

 

[kingofnobbys]

I was looking for that, mislaid the url for it.
From data in the UV report
http://www.uvguide.co.uk/fluorescenttubemeshtests.htm
Graph 1 see below :

can see the follow data for a tube in a reflector series 4 and 5. (the mesh tested was "no4 plane mesh" aperture 5mm).

The explanation is the mesh is positioned very close to the tube, so we have light coming from a wide range of direction, not all coming from a distant point source (with the ramifications pertaining to that where all the rays of light are travelling in one direction in x,y and z).

Still very close to figures given already (ie about 30% blockage) .

 

[LANING1]

The mesh is 2mm square

 

[kingofnobbys]

The mesh is 2mm square

Sounds like flyscreen.
Same data set used to calculate the flyscreen (2mm mesh) blocks 38% of the UV. NOT 72%

(I took data from the wrong curve - very similar colours - have to look REAL CLOSE to see the difference) ...my apologies....still best mounting your UV light under mesh even if it's a T5ho in a nice well designed reflector hood.)

 

[AHBD]

I agreed that some screen blocks up to 30%....the o.p specifiacally stated that he had read that it blocks 50%....that was why I replied that it's not that much. But the tests on reptile screening did not show results of 72% being blocked. I hope this doesn't sound like an argument, but please see the chart that I attached up above from the uk uv guide....the testing was done specifically on screen that is used for reptile tanks, using larger gauge screen as well as the fly mesh. The fly mesh type screen on chameleon cages , which would be the very smallest used on a reptile tank, blocked about 25-35% uvb. This is an independent group, not the producers of the bulbs....they checked several types of bulbs + screen, that's what is relevant here.

Here it is again for anyone who might not have seen it.

https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=2&cad=rja&uact=8&ved=0ahUKEwicjKzL16TVAhWIOiYKHUIzBpgQFggvMAE&url=http%3A%2F%2Fwww.uvguide.co.uk%2Ffluorescenttubemeshtests.htm&usg=AFQjCNEblaL0mKNp5_C2jh6Rckx3w67ucg

 

[kingofnobbys]

I agreed that some screen blocks up to 30%....the o.p specifiacally stated that he had read that it blocks 50%....that was why I replied that it's not that much. But the tests on reptile screening did not show results of 72% being blocked. I hope this doesn't sound like an argument, but please see the chart that I attached up above from the uk uv guide....the testing was done specifically on screen that is used for reptile tanks, using larger gauge screen as well as the fly mesh. The fly mesh type screen on chameleon cages , which would be the very smallest used on a reptile tank, blocked about 25-35% uvb. This is an independent group, not the producers of the bulbs....they checked several types of bulbs + screen, that's what is relevant here.

Here it is again for anyone who might not have seen it.

https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=2&cad=rja&uact=8&ved=0ahUKEwicjKzL16TVAhWIOiYKHUIzBpgQFggvMAE&url=http%3A%2F%2Fwww.uvguide.co.uk%2Ffluorescenttubemeshtests.htm&usg=AFQjCNEblaL0mKNp5_C2jh6Rckx3w67ucg

oops !
I saw two curves which looked black , but the correct one for flyscreen was darknavy .... so the correct figures are