If you've ever found yourself in the market for a tent, you've probably noticed that different models come with a water or aqua rating listed in the specifications. But what exactly does this rating mean, and how does it impact your decision-making process? In this straightforward guide, we'll break down the meaning behind these ratings, specifically for those planning camping trips in beautiful New Zealand. We'll explain how these ratings are determined, highlight the key factors you should consider, and give you an honest assessment of how our Kiwi Camping tents fare in comparison.
What is a water tent rating?
A water tent rating, or aqua rating, determines how well a tent can withstand water pressure. It is measured in millimetres (mm), usually falling within the range of 800 to 10,000. For example, a tent with a 4,000mm aqua rating can endure the pressure of 4,000mm or a 4-meter column of water before it starts to leak.
How are these ratings determined?
Tent manufacturers employ Hydrostatic Head (HH) testing to assess the waterproofness of tent fabrics. HH refers to the material's ability to resist water. During testing, a fabric sample is clamped at the base of a transparent graded tube. Gradually, water is poured into the tube, and experts observe the fabric for any signs of water penetration. The height water starts seeping through the material determines its waterproof rating.
Protective coatings are applied to the fabric to enhance a tent's waterproof properties. These coatings seal the gaps between threads, preventing water from passing through and allowing it to bead and run off the surface. Typically, polyester fabrics are treated with polyurethane (PU) coatings, while nylon fabrics utilize silicone (sil) coatings. The application process, including the thickness and number of coatings, is carefully chosen to achieve the desired Hydrostatic Head.
For more information about Hydrostatic Head testing, check out this blog here.
Is a higher water rating always better?
Tents serve different purposes and face various stresses, such as sunlight, strong winds, poor weather, and rough, damp ground. While higher Hydrostatic Head (HH) fabrics offer greater rigidity and durability, they can also be heavier and may not be necessary for the specific conditions you'll encounter.
It's important to note that HH is just one factor in determining a tent's ability to withstand water pressure. Even a tent with a 10,000mm rating can leak if it lacks proper stitching or sealing. Additionally, if a tent needs to be better designed, water can find its way through areas like zippers or windows.
Which water ratings for which conditions?
Typically, the floor of a tent has a higher rating than the fly because it endures added stress from campers and constant contact with the ground. Consider the season you'll be camping in and check the local weather conditions.
In New Zealand, where downpours can occur even in the height of summer, 2- and 3-season tents should have fly waterproof ratings exceeding 1,500mm and floor ratings surpassing 3,000mm to withstand most winds and rain. On the other hand, 3- and 4-season tents designed for year-round camping in any month and anywhere in NZ should provide protection against heavy rain and light to substantial snow. For such tents, look for fly ratings of at least 3,000mm and floor ratings ranging from 5,000-10,000mm.
