What Is Hydrostatic Head? Waterproof Ratings Explained
Embarking on thrilling outdoor expeditions demands reliable gear that can brave the elements. In order to enjoy your adventure to the maximum we understand the critical role of waterproof ratings and hydrostatic head in ensuring you remain dry and comfortable throughout your journeys. We’re going to break down what is hydrostatic head and the waterproof ratings around them so you can discover your world.
What Is Hydrostatic Head?
A hydrostatic head test assesses a fabric's waterproofing abilities by subjecting it to increasing water pressure. The fabric is set up in a sealed tube, and water is applied gradually until leakage occurs. The pressure at which water penetrates the material determines its hydrostatic head rating, indicating its waterproof capacity. Fabrics with higher ratings are better suited for harsh weather conditions, while those with lower ratings are suitable for milder climates.
The test is conducted in adherence to industry standards set by organizations like ASTM and ISO, ensuring consistency and reliability. Manufacturers use this evaluation to determine the fabric's applicability in various outdoor gear. Ultimately, the test guarantees that outdoor enthusiasts can rely on their gear to provide effective protection against water, allowing them to enjoy outdoor activities confidently and comfortably, regardless of the weather. Hydrostatic Head then helps establish what people commonly refer to as 'waterproof ratings'.
To meet the correct UK standard the fabric must pass a result of 1500mm or more.
Decoding Waterproof Ratings
On our website you may have seen next to our waterproof products some numbers such as 8,000ml through to 30,000ml and thought 'what on earth does this mean?', These numbers are our hydrostatic head/waterproof ratings in practice! The higher the number, the more water pressure that specific product can endure, providing you with more waterproof protection.
Waterproof Rating Recommendation
You may now be thinking 'What waterproof rating do I need?', it can be confusing to try and understanding what level of protection you need, and it all depends on your activity, location and of course the climate! We have the following recommendations below:
Up to 5,000mm: Light Rain
5,000mm - 10,000mm: Average to Heavy Rain
10,000mm & Above: Very Heavy Rain
What Is Breathability
Breathability is the amount of water vapour that can be let out through a fabric. Testing the breathability of our clothing involves checking how well the fabric allows sweat to escape. They use a method called moisture vapor transmission rate (MVTR) testing. This measures how quickly moisture passes through the fabric over a specific time. Higher MVTR values mean the fabric is more breathable, making it more comfortable during outdoor activities. Conducting these tests ensures clothing efficiently manages sweat, keeping adventurers cool and dry during their journeys.
Breathability has a similar scale to our waterproof rating, the higher the number, the more breathable the garment is going to be. Breathability is measured in g/m2/24hrs.
Ensuring Longetivity & Performance
To maximize the lifespan and performance of your Craghoppers gear, follow our maintenance guidelines diligently. From routine reapplication of waterproof coatings to avoiding unnecessary wear and tear, nurturing your gear as per our recommendations guarantees that it continues to safeguard you during every exhilarating expedition.
You can check out our guides to washing and re-waterproofing your waterproof jackets below.
