Wednesday 9 October 2013

Grade 3 Explained: Motorhome & Caravan Winterisation

TankBlanket:  Winterisation that Works

TankBlanket: The Water Heater presents:

Motorhome & Caravan  Winterisation: Grade 3 Explained!
As I write, the October NEC Motorhome and Caravan Show is a matter of days away and with the economy showing signs of strengthening, expectations are high for a good Show.

At this point it seems 2014 will be defined by models that are marketed as energy efficient and winterised. This blog will discuss Grade 3 and winterisation.

The Consumer will be bombarded during the October show  with stickers displayed on product and brochures that declare 'this motorhome is Grade 3 accredited' and is a ‘winterised’ vehicle that can be used ‘all year round’. So what is Grade 3 and what does ‘winterisation’ mean?

Simply, Grade 3 is a British standard for heating and insulation while ‘winterisation’ is a term open to a plethora of interpretation, but for this blog, it is taken to mean a motorhome that can be used in freezing conditions with free flowing fresh and waste water.

Grade 3 emanates from the British standard BS EN 1646-1:2012 titled ‘Leisure accommodation vehicles – Motor caravans part 1: Habitation requirements relating to health and safety’.  Within section 9 of this standard is the detail relating to three levels of motor caravan heating. These are:
Grade 1: No heating.

Grade 2:  When the outside temperature is 0°C the internal temperature must be held at an average of at least 20 °C for a defined period of time.

Grade 3: When the outside temperature is -15°C the internal temperature must be held at an average of at least 20 °C for a defined period of time.

The test has to be performed under controlled conditions and is subject to certain criteria so results can be reproduced and compared with statistical integrity. The standard states that the test should be performed in a cold chamber with temperature probes located at specific points.

The test is subject to four time based criteria. These are:

Phase 1: The vehicle is soaked a in cold chamber for at least 10 hours to achieve a temperature of 0 °C or -15 °C throughout, depending whether it is a grade 2 or 3 test.

Phase 2: Upon reaching its soak temperature the habitation heating system is switched on and the vehicle is given up to 2 hours or 4 hours to achieve an internal temperature of 20 °C, again, depending whether it is a grade 2 or 3 test.

Phases 3 & 4: Once the internal temperature of 20 °C has been achieved a 1 hour stabilizing period commences before monitoring of the thermal energy consumption takes place.

 This is the important statement for those wishing to use their vehicle throughout the year:

The standard states that ‘precautions’ should be taken to ensure that the fresh water system can be charged at the end of the 1 hour stabilising period (phase 3) and operate while the external temperature is at -15 °C.

This means the business end of the test is performed with a dry vehicle and water is only added at the end of the one hour stabilising period, that is, when the vehicle's internal temperature is at 20°C.

If the vehicle under test achieves all of the above criteria then it is accredited as a Grade 3 Motorhome.

So, Grade 3 is a thermal insulation and heating standard. A motorhome with Grade 3 will keep you warm in freezing conditions but it will not provide you with free flowing fresh and waste water during sub zero temperatures.
So, who in the UK manufactures a genuinely ‘winterised’ motorhome, one that can be used all year round with confidence that the water system is not going to freeze up? Let's see what 2014 brings!

In our next blog, insights gained from cold chamber testing of TankBlanket, the water tank heater, will be discussed. So, why not follow us?
TankBlanket : The water tank heater


  1. I am happy to find your distinguished way of writing the post. Now you make it easy for me to understand and implement the concept. Thank you for the post.
    Rent campervan New Zealand

  2. I am a new user of this site so here i saw multiple articles and posts posted by this site,I curious more interest in some of them hope you will give more information on this topics in your next articles. valutazione camper mclouis


Fresh & Waste Water : Tank Level Indicators - That Work!

An inaccurate level reading from either your fresh or waste water tank is frustrating! But, now, direct from the USA,  Premier Leisu...