Airflow thru 6 mesh, .035 gauge screen

Click For Summary

Discussion Overview

The discussion revolves around the impact of using a 6 mesh, .035 gauge wire screen on a chimney to prevent bees from entering while ensuring proper venting for a gas fireplace. Participants explore the airflow characteristics of different mesh sizes and their implications for chimney safety and bee exclusion.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant expresses concern about whether a 6 mesh screen will adequately prevent bees from entering the chimney while allowing safe venting for gas logs.
  • Another participant notes that the 6 mesh screen has a free area of 62%, suggesting that airflow reduction depends on the screen's restriction relative to the overall system pressure drop.
  • Some participants mention that chimneys are likely oversized, implying that as long as there is a positive draft and no spillage, the screen may not pose a significant issue.
  • There is a discussion about the effectiveness of a "queen excluder" mesh, which could prevent a swarm from nesting in the chimney but may not stop individual bees from entering.
  • One participant reassures that there should be no problem with venting through the 6 mesh screen, noting its dimensions in relation to the queen excluder and the behavior of different types of bees.

Areas of Agreement / Disagreement

Participants express varying opinions on the effectiveness of the 6 mesh screen for both bee exclusion and airflow. While some suggest it should work well, others highlight uncertainties regarding airflow reduction and the potential for different bee species to enter.

Contextual Notes

Participants reference specific measurements and characteristics of the mesh screens, but there are unresolved questions about the overall impact on chimney venting and bee behavior.

Who May Find This Useful

This discussion may be useful for homeowners dealing with similar issues of pest exclusion and venting safety, as well as those interested in the technical aspects of airflow through mesh screens.

veithmoore
Messages
5
Reaction score
0
Happy Holidays! I saw your posting on airflow thru mesh screen and went to Perry's looking for answers. I haven't found what I'm looking for yet and was wondering if you can help?

Our problem concerns bees coming down the chimney and how to stop them.
We installed a Lymance chimney damper with a sealing gasket but not sure if it will stop the bees come next spring.
Planning on using 6 mesh, .035 diameter wire screen placed on the spark arrestor to make sure.

We installed gas fire logs and have a question on how the 6 mesh screen will impact venting thru the chimney.
The best info I found was from a company the makes screens for hot water heater vents. They sell an 18 mesh screen that says it provides 70% airflow. Would that mean a 6 mesh screen would provide 90% airflow?

No one seems to want to answer the question of the impact of placing the 6 mesh screen on my chimney cap, regarding the safety of venting the gas log fireplace.
Any input would be appreciated! Thanks, Veith
 
Last edited by a moderator:
Engineering news on Phys.org
I had to google this: that's 6 wires per inch, and 62% free area. Airflow reduction depends on free area and system pressure drop. In other words, the airflow reduction depends on how much of a restriction this is vs the rest of the system.

Anyway, my suspicion is that chimneys are probably vastly oversized and as long as you can see a positive draft and no spillage into the room its probably fine.
 
russ_watters said:
I had to google this: that's 6 wires per inch, and 62% free area. Airflow reduction depends on free area and system pressure drop. In other words, the airflow reduction depends on how much of a restriction this is vs the rest of the system.

Anyway, my suspicion is that chimneys are probably vastly oversized and as long as you can see a positive draft and no spillage into the room its probably fine.
Thanks, happy holidays!
 
Is it a couple of bees, or a swarm building a nest in the chimney that is the problem?

There is a mesh used in a hive called a "queen excluder" that allows workers and drones to pass, but stops the larger queen from passing up into the honey store. The gaps are 0.163 inches (4.1 mm). That will not prevent bees entering, but since the swarm follows the queen, it should prevent a swarm building a nest in the chimney.
https://en.wikipedia.org/wiki/Queen_excluder

More smoke will pass through a long slot than a square mesh of the same width.
 
Baluncore said:
Is it a couple of bees, or a swarm building a nest in the chimney that is the problem?

There is a mesh used in a hive called a "queen excluder" that allows workers and drones to pass, but stops the larger queen from passing up into the honey store. The gaps are 0.163 inches (4.1 mm). That will not prevent bees entering, but since the swarm follows the queen, it should prevent a swarm building a nest in the chimney.
https://en.wikipedia.org/wiki/Queen_excluder

More smoke will pass through a long slot than a square mesh of the same width.

We were out of town and came home to a hive inside the house. The bee keeper came and took the queen which caused the swarm to follow her outside. We cleaned up all the dead ones but the bee keeper said they would come back because our house had been marked. They did return the next spring but we had put window screen over the chimney opening on the roof, but couldn't use the fireplace.
We changed to a gas fire log setup and are concerned about venting with 6 mesh by .035 gauge screen over the spark arrestor on the roof. Thanks for the reply! Veith
 
veithmoore said:
We changed to a gas fire log setup and are concerned about venting with 6 mesh by .035 gauge screen over the spark arrestor on the roof.
There should be no problem with a gas fire venting through that screen.
The #6 mesh size, woven from 0.035" diameter wire, with 0.132" openings, is slightly smaller than the queen excluder 0.163", so it should keep queen bees out. It may also keep out the other members of the swarm.

European honey bees have a standard size. But there are many other types of bee, some are bigger, some smaller.

The odd robber bee may visit, following the scent of the earlier swarm, but if there is no honey or sugar to steal, it will not return with its colleagues. With time the scent will fade.
 
Baluncore said:
There should be no problem with a gas fire venting through that screen.
The #6 mesh size, woven from 0.035" diameter wire, with 0.132" openings, is slightly smaller than the queen excluder 0.163", so it should keep queen bees out. It may also keep out the other members of the swarm.

European honey bees have a standard size. But there are many other types of bee, some are bigger, some smaller.

The odd robber bee may visit, following the scent of the earlier swarm, but if there is no honey or sugar to steal, it will not return with its colleagues. With time the scent will fade.
Thanks for the reply, very helpful. Veith