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What’s the difference between holes per square inch and mesh size?

Holes per square inch is defined as the number of openings in one square inch of material.

Mesh size is referring to the mesh number and its relationship to the size of the openings in the mesh and thus the size of particles that can pass through these openings.

How do I calculate holes per square inch (psi)?

Figuring out the mesh number is simple. All you do is count the number of openings in one linear inch of screen. This count is the mesh number. A 4-mesh screen means there are four little square openings across one inch of screen. A 100-mesh screen has 100 openings per inch, and so on.

As the number indicating the mesh size increases, the size of the openings and thus the size of particles captured by the screen decreases. Higher mesh numbers = smaller particle sizes.

What holes per square inch is best for keeping mosquitoes out?

Mosquitoes are bigger than midges, which means the mesh size can be slightly bigger. This means the holes per square inch can go from 150 psi – 400 psi.

How about midges?

Midges, being smaller need a smaller mesh size. Meaning the holes per square inch needs to be bigger, so anything from 600 psi – 3000 psi will do the job.

What’s the difference between the midge net holes per square inch?

3000 holes per square inch sounds great, right? So, why would you want anything less than that? Well, it’s all down to what we call breathability.

What does breathability mean?

The technical term is defined as the ability of a fabric to allow perspiration, evaporated by the body, to escape (diffuse) to the outside (termed moisture vapour transmission), thereby allowing complete comfort.

In Layman’s terms, the more holes per square inch – the less air can flow through

the less holes per square inch – the more air can flow through

You need to decide how hot the place will be you are going to, as you don’t want to be in 30 degree heat with a less breathable mesh. If it’s a bit cooler and you’re not confined to a camper van, the less holes per square inch will be just as effective.

How about visibility?

The same rule of thumb applies. If the mesh has more holes per square inch, the holes will be tighter together, making visibility a little more difficult than a 600 holes psi for example. This is why we have included visors in our Purple Turtle Head Net with Visor, so you have the option of better visibility. This is great for outdoor activities like bird watching, train spotting or fishing in a midge infested area.

What does treated and untreated mean?

If a mosquito net or netting is impregnated (treated), this means it’s treated with an insecticide to kill any flying insect that touches the net. The treated nets do not repel mosquitoes – they deliver insecticide very rapidly after the briefest contact to kill the flying insect.

The distribution of mosquito nets or netting impregnated with insecticides such as permethrin has been shown to be an extremely effective method of malaria prevention. Treated nets protect people sleeping under them and simultaneously kill mosquitoes that contact the nets.

The untreated nets do not have any insecticide treatment. Click here for untreated nets.

Are the treated nets harmful to humans?

No. These insecticides have been shown to pose very low health risks to humans and other mammals, but are toxic to insects and kill them.

Can I treat my own net?

Yes, we have a product called Lifesystems EX4 Permethrin Clothing Treatment which is used to spray fabrics, textiles and other materials to help prevent insect bites.

Please click here to read about Permethrin.

Why are mosquito nets treated but head nets aren’t?

Mosquito nets are either treated or untreated. Some mosquito nets are now available as untreated due to the risk of ingestion of the chemicals on the net. It is for the same reason midge head nets and midge jackets are untreated, due the proximity to your face this poses a risk.

The head nets and jackets have a much finer mesh (600 holes / sq inch) so no insect can get through to increase the protection the user has.

As far as we are aware it is industry standard for head nets to be untreated.

So is it about ingestion or proximity to the face?

It is a mixture of both, with it being close to your face it increases the chances of ingestion/inhalation. Most mosquito nets have a warning on the tags to avoid prolonged direct contact with the skin. It is not going to cause a problem straight away but the treatment is designed to kill insects on contact so you can see why it is not recommended. For example, a baby is more likely to chew or place the net into their mouth hence why the cot nets are untreated.