Tent Fabric, Specifications and Coatings Explained

Lets take the myth and confusion out of Tent Specifications and jargon! It's important that you choose the best tent for your needs so lets quickly look at the terminology you will find in Tent specifications from manufacturers.

When looking at tents for sale, reputable brands and retailers should provide tent fabric specs so you can work out a tent’s performance capabilities and suitability to handle different conditions. Here's an introduction to different tent fabric specifications.

Hydrostatic Head (HH), water column or ‘waterproof’ ratings (measured in mm)

Polyester and nylon fabrics are not waterproof and so silicone or PU coatings are applied to give waterproof properties. The amount of water that they can ‘hold out’ is tested using a high column of water which is measured in mm. Ratings range from 800mm up to a max of 10,000mm with ratings of 1500mm and higher generally considered ‘waterproof’.

All our tents have a rating of 3,000mm so are extremely reliable in bad weather!

What is Denier?

Denier (D) is the unit measuring the weight and thickness of the individual threads used in the fabric. Fabric with a higher Denier will be thicker, stronger and more durable than the same fabric with a lower Denier – 40D Nylon will be stronger than 15D Nylon and 70D Polyester stronger than 50D Polyester. Remember that different fabrics have different strengths. Lower Denier is common in ultralight nylon tents and tarps where low weight is paramount. 

All Kelly Kettle camping tents are Polyester 70D. Something like a heavier duty event shelter may be in the region of 150D as thicker material would be required to deal with greater stresses and longer exposure to the sun and elements.

What is Thread count?

The thread count (T) is the number of threads used horizontally and vertically per square inch of fabric ... 190T means a total of 190 threads. A higher thread count represents a greater density and tighter weave in the fabric. For this reason you will often find lower Denier fabrics (with a ‘thinner’ thread) have a higher thread count.

All Kelly Kettle Tents have 190T whereas our standard Tarp has 210T.

What is Ripstop?

Ripstop tent fabrics are those with a special reinforcement to increase resistance to tearing and ripping. When weaving, a stronger thread is used at regular intervals to form a crosshatching, grid pattern visible in the fabric. This improves strength of the fabric and makes any tears or holes less likely to spread and become bigger.

We use the Ripstop fabric in ALL our Tarps & Tents to give you the best product available.

What are fabric coatings?

Chemical coatings are applied to tent fabrics to increase their performance, especially resistance to water. What is a silicone coating? What is silnylon? A silicone coating is usually applied to nylon, hence 'silnylon'. The coating ‘permeates’ the nylon fabric creating a stronger silicon ‘reinforced’, waterproof nylon fabric with better stretch and tear strength. Silicone repels water and so it’s easy to shake off excess water and dries quickly. On the down side silicone coatings are more expensive, stop ‘breathing’ in the fabric which may lead to greater condensation, and result in a very slick and slippery surface meaning that tent seams cannot be taped - Silnylon seams require manual application of a liquid seam sealant.

Our Ultralight Tarp is made from Ripstop Silnylon fabric and waterproof to 3000mm & UV50 to protect you from the suns harmful rays.

What other fabric coatings are there?

A number of other coatings can be applied to tent fabrics to improve UV resistance, water resistance (allowing water to bead and roll off), rot and mildew resistance and to add fire retardant properties to fabrics.

Kelly Kettle Tarps & Beach Shelter provide UV50 protection.

What is Fire Retardant CPAI-84

CPAI-84 is a testing method used specifically for confirming the flame resistance of fabric used in manufacturing camping tents. Suppliers must submit the various tent materials (ceiling, walls, and floor) to a third-party organization licensed to perform the required CPAI-84 flame retardancy testing. Suppliers of the tent materials that meet these standards are then awarded an official laboratory approved certificate that can be shared with their customers.

History of the Test:  In 1976, the CPAI (Canvas Products Association International), now known as the International Fabrics Association International, set the flammability standards for camping tents as means to help protect consumers by limiting accidents caused by flames near the vicinity of camping tents. The test does not declare that the material if fire proof if exposed to a continuous flame. Rather the CPAI-84 test confirms fire resistance after the material is exposed to a flame.

ALL Kelly Kettle Tents, Tarps & Beach Shelters are Fire Resistant and comply with CPAI-84

Notes on Materials

Polyester has a higher intrinsic durability than nylon. Better abrasion resistance and exposure to ultraviolet radiation. Polyester behaves better in bad weather conditions, heavy rain and strong wind. It is harder, and less permeable to water vapor than simple nylon. Polyester is less ” breathable ” than nylon. It`s holds less water than nylon. Polyester is usually padded with polyurethane (PU).
Ripstop technology refers to a technique of weaving where fibers are interwoven in a cross shape. This significantly improves the final layering and prevents the material from unraveling. Polyester is generally considered better than nylon in camping tents and/or mountain/family tents.

Ripstop Nylon (polyamide) with silicon coating. Silicon coated materials are not hydrophilic - water vapor can not pass through them. Water does not get into the material, but it forms a pellicle on the surface of it. Instead, it is extremely resistant to bad weather conditions. It also behaves much better to UV radiation and this is extremely important for mountain expeditions at high altitudes (over 4000 m).


What to look for in your next tent fabric specs? Generally, the higher the denier count the stronger and heavier the fabric will be, and the higher the mm rating the more ‘waterproof’ it will be. Have a look at the following ... 70D 190T Polyester Ripstop 3000mm CPAI-84 – a high quality polyester, fire-retardant tent fabric suitable for bad weather that is rip resistant.  Perfect for camping tents.  All our tents have this high specification. 

40D Ripstop SilNylon 3000mm – a light 40 Denier nylon fabric suitable for ultralight tents or tarps, ripstop so has better tear resistance, silicone coating topside and underside, good waterproof rating at 3000mm should be able to deal with most rain.  Our Ultralight Tarp is made from this material.

We hope this page has helped clear any confusion about materials and specifications etc.  Our motto here at the Kelly Kettle Company is 'Outdoor Life Enjoyed'.  We hope that our very affordable range of high quality Tents & Tarps will allow you to 'get out' and enjoy life in the great outdoors!