Awning flooring and heating

[Parksy]

We all had coal fires at home when I was a kid Buckman.
One of my abiding memories of rooms 'heated' by coal fires was the competition to sit as close as we could to the fireplace. If we managed to escape parental wrath, because they swore blind that we'd get chill blains or be sick, and to elbow the dog to one side, the front of our bodies became nice and warm, but there was always a strong draught at our back, so although our front was warm our backs were freezing. We'd stand up and turn our backs to the fire to warm up.
The reason for the cold draught was that hot air rises so the chimney drew the air from the room, it helped to fuel the fire and went up the chimney.
Houses in those days had ill fitting doors and windows, with no double glazing or sealed doors like we have these days. Coal fires would be lethal in modern homes.
Awnings do allow a small amount of air circulation but the roofs are not vented, so lethal C O given off by fuel burning appliances has nowhere to go, and could be breathed in.
These same fumes went straight up the chimney in older houses, but awnings don't have chimneys.

 

[Buckman]

Thanks Parksy as wondering why I am still here taking into consideration the hazards we were subjected to as kids. LOL!

 

[Parksy]

:cheer: :cheer: :cheer:
We did well to survive mate :evil:

 

[Raywood]

I think you have to go to the Prof's post. Essentially CO is about the same weight as CO2, but because it is coming from a heater it then it rises, so if the awning is a tight fit against the caravan walls then you will get a build up of CO from the roof downwards. The gaps are at the base so the CO is pushing the other gasses out the bottom rather than getting out itself and the danger therefore is very real if you use are using gas appliance in the awning. Their have been deaths because of this, although I cannot remember seeing any recent reports.
I appreciate the points made about coal fires but they were used with a chimney which took most of the hot air and dangerous gasses away and the radiant heat heated the room, which is why they were very inefficient compared with gas and electricity. Badly ventilated gas fires though have caused quite a few deaths.

 

[Hutch]

In our house , we have a ground level ventilation tunnel from outside to the boiler house, the gas board then said we needed a high level one, with an insect grid, next year, remove the grid in case insects block it. So we can have a lovely sound of a howling wind on some days in the well ventilated boiler house.

Back to the Awning, I would never use a gas heater, or BBQ in an awning, and ours has a vent at both corners at the top next to the caravan walls.

 

[ProfJohnL]

:silly:

...Badly ventilated gas fires though have caused quite a few deaths.

Further to ray's comment, back the 40's 50 and 60's there were a spate of deaths resulting from exposure to CO, where open flue water heaters had been fitted in bathrooms.

Open flued gas water heaters were a fairly common product in those days, but they relied on taking air from the room in which they were fitted to burn the gas, and the flue pipe often had what I believe was back draft diffuser which was basically an inverted funnel over the top of the heater and the flue was not sealed to the heater.

Most of the victims were in a room (often the bathroom) where the heater had been fitted. It was cold so the user had put some sort of draught excluder at the bottom of the door. What they hadn't realised was this would restrict the necessary air flow into the room to allow the heater to burn properly. With a restricted air flow into the room there was not enough net air exchange with the fresh outside air, this also affected the ability of the flue to "draw" convected products of combustion away, The result was the flue products would eventually start to build up in the room.

A similar situation could also arise, if the flue had wind acting directly against it. It would baffle the exit of the flue products and again they would start to build up within the room, even if the draught under the door had not been blocked off. Smaller rooms exacerbate the problem.

As result of these and fewer but similar incidents involving other open gas fired appliances, the law was changed, and it required most open flamed appliances to automatically detect reducing oxygen levels and shut off, or to make the appliance room sealed, - which is a bit of a misnomer, as it actually means sealed from the room to prevent the mixing of combustion air and products of combustion with the occupied living space. This is why it is illegal to fit any (except cooker hobs and ovens) in touring caravans. This is one reason why caravan are still required to have what is called fixed ventilation at both high and low levels to facilitate enough free exchange of air with the outside.

Virtually every caravan heater installed since 1970 is room sealed, either like the Carver/Truma 1.6kw series with an underfloor balanced flue, or their larger cousins with a roof mounted chimney which is driven by the thermal convection from the flame and draws air from under the caravan.

The legal issues led to the development of Balanced flues as used on Carver,Truma, Malaga side wall mounted water heaters. With the increase in the number of remote gas appliances not necessarily fitted to an outside wall,fan assisted flues have been developed such as we find on the Propex and Truma E series heaters and most domestic condensing domestic boilers.

 

[Buckman]

:silly:

.
Virtually every caravan heater installed since 1970 is room sealed, either like the Carver/Truma 1.6kw series with an underfloor balanced flue, or their larger cousins with a roof mounted chimney which is driven by the thermal convection from the flame and draws air from under the caravan.

However what about fridges fitted into caravans as it seems many to be fitted poorly and are not sealed in correctly. This is noticed as per the draughts you get or in hot weather not cooling down properly?

 

[Dustydog]

:silly:

.
Virtually every caravan heater installed since 1970 is room sealed, either like the Carver/Truma 1.6kw series with an underfloor balanced flue, or their larger cousins with a roof mounted chimney which is driven by the thermal convection from the flame and draws air from under the caravan.

However what about fridges fitted into caravans as it seems many to be fitted poorly and are not sealed in correctly. This is noticed as per the draughts you get or in hot weather not cooling down properly?

There are two aspects here. The sealing of the fridge in its housing is not as critical as a good fitting flue and correctly adjusted flame. The draft we sometimes get from the fridge to me anyway proves the vents are working properly. A lot of people have sealed the fridge to cabinet edge with some forof insulation. Do not block off any of the floor vents or rear vents.
I doubt the volume of gas used, generally180 gms over 24 hours on an average unit will create enough CO to damage you providing all the above is in order.

 

[ProfJohnL]

...However what about fridges fitted into caravans as it seems many to be fitted poorly and are not sealed in correctly. This is noticed as per the draughts you get or in hot weather not cooling down properly?

Dusty has given a good answer, but to fill out a bit more of the relevant information.

You may be forgiven for thinking that a "room Seal" should be 100% gas or fume tight, but there are permitted limits layed down in the gas appliance construction regulations, which are many fold and I no longer have access to a set, so I can't quote chapter and verse (many will be thankful for that)

In essence the required quality of a room seal is determined by the amount of gas an appliance consumes, so the seal is less stringent for small consumption appliances etc. But having said that it is not difficult to produce a good room seal that exceeds the required standard.

Fridges do have a relatively small gas consumption (typically about 120W) so they will produce less fumes than say a gas space heater rated at 3kw. and if you read the fridge manufacture's instructions it does instruct the fitter on the need to create a room seal. The fact that most caravan installations don't achieve the required room seal is a sore point and other contributors and I to this forum have bemoaned the situation on a number of occasions.

I am in no way condoning the poor fitting of fridges or any other gas consuming appliance, and it should be the fitters aim to exceed the room seal requirements BUT, whilst the fridge seal to the caravan may be poor in many instances the consequences are frequently mitigated by other circumstances.

As already mentioned the size of the gas burner is relatively small, its far less than a gas flame on a hob or oven. A properly maintained fridge will burn relatively cleanly minimising the most dangerous CO flue products.

Due to the large exterior ventilation grills provide, the fridge will preferentially take its air for combustion from outside, so there will little opportunity for the fridge to re-ingest its own fumes or draw air from inside the caravan.

Most fridges are designed with a flue that directs the products of combustion to the exterior grill even though the connection between the two is relatively loose. This should under most circumstances still mean the majority of the flue products will pass to the outside rather than be directed into the caravan. This will be assisted by the thermal drive of the cooling air passing over the condenser radiator coils on the back of the fridge.

If the wind conditions are such that the flue product is baffled and cannot escape through the exterior grill, the volume of fresh air pushing it back will also dilute the products of combustion further reducing their potential impact. But at the same time if the air and flue product is able to pass into the caravan around the fridge, it will only do so if there is an almost equal freedom for the air to escape the caravan through its other ventilation. so the percentage mixture of fridge derived CO will be very small.

I'm not claiming there is no danger, for example if the fridge has not been maintained correctly and is burning with very poor quality combustion, the levels of CO produced may be enough over a few hours to be a problem, either inside a poorly ventilated caravan or awning.

The poor room sealing of fridges should have no effect on the fridges cooling performance. That is a totally separate issue.

 

[otherclive]

...However what about fridges fitted into caravans as it seems many to be fitted poorly and are not sealed in correctly. This is noticed as per the draughts you get or in hot weather not cooling down properly?

Dusty has given a good answer, but to fill out a bit more of the relevant information.

You may be forgiven for thinking that a "room Seal" should be 100% gas or fume tight, but there are permitted limits layed down in the gas appliance construction regulations, which are many fold and I no longer have access to a set, so I can't quote chapter and verse (many will be thankful for that)

In essence the required quality of a room seal is determined by the amount of gas an appliance consumes, so the seal is less stringent for small consumption appliances etc. But having said that it is not difficult to produce a good room seal that exceeds the required standard.

Fridges do have a relatively small gas consumption (typically about 120W) so they will produce less fumes than say a gas space heater rated at 3kw. and if you read the fridge manufacture's instructions it does instruct the fitter on the need to create a room seal. The fact that most caravan installations don't achieve the required room seal is a sore point and other contributors and I to this forum have bemoaned the situation on a number of occasions.

I am in no way condoning the poor fitting of fridges or any other gas consuming appliance, and it should be the fitters aim to exceed the room seal requirements BUT, whilst the fridge seal to the caravan may be poor in many instances the consequences are frequently mitigated by other circumstances.

As already mentioned the size of the gas burner is relatively small, its far less than a gas flame on a hob or oven. A properly maintained fridge will burn relatively cleanly minimising the most dangerous CO flue products.

Due to the large exterior ventilation grills provide, the fridge will preferentially take its air for combustion from outside, so there will little opportunity for the fridge to re-ingest its own fumes or draw air from inside the caravan.

Most fridges are designed with a flue that directs the products of combustion to the exterior grill even though the connection between the two is relatively loose. This should under most circumstances still mean the majority of the flue products will pass to the outside rather than be directed into the caravan. This will be assisted by the thermal drive of the cooling air passing over the condenser radiator coils on the back of the fridge.

If the wind conditions are such that the flue product is baffled and cannot escape through the exterior grill, the volume of fresh air pushing it back will also dilute the products of combustion further reducing their potential impact. But at the same time if the air and flue product is able to pass into the caravan around the fridge, it will only do so if there is an almost equal freedom for the air to escape the caravan through its other ventilation. so the percentage mixture of fridge derived CO will be very small.

I'm not claiming there is no danger, for example if the fridge has not been maintained correctly and is burning with very poor quality combustion, the levels of CO produced may be enough over a few hours to be a problem, either inside a poorly ventilated caravan or awning.

The poor room sealing of fridges should have no effect on the fridges cooling performance. That is a totally separate issue.

Thank you Prof. I would just add that a properly installed and working CO detector is an invaluable backstop, particularly if tested regularly too.

 

[VicMallows]

I have been interested in the question of possible CO build-up within an awning when the fridge vents into the awning space .... largely because I quite often sleep in the awning!

In context, I should mention that I use a full awning, with draft skirt, on a very small caravan (Elldis 362). Using a display-type domestic CO alarm, I have never seen anything at all when using the 'van in the UK, wherever I place the detector.
On a particularly hot, still day in Spain recently (fridge working flat out on gas) I thought I'd check the level in the awning while out for the day with the awning closed right up.
On return, the detector was indicating a peak level of 55ppm , measured about 1m above ground ...... still way below any danger/alarm level.

Inside the 'van I have never seen anything above 15ppm, even with the cooker in extensive use, and usually it is zero.

 

[ProfJohnL]

I have been interested in the question of possible CO build-up within an awning when the fridge vents into the awning space .... largely because I quite often sleep in the awning!

In context, I should mention that I use a full awning, with draft skirt, on a very small caravan (Elldis 362). Using a display-type domestic CO alarm, I have never seen anything at all when using the 'van in the UK, wherever I place the detector.
On a particularly hot, still day in Spain recently (fridge working flat out on gas) I thought I'd check the level in the awning while out for the day with the awning closed right up.
On return, the detector was indicating a peak level of 55ppm , measured about 1m above ground ...... still way below any danger/alarm level.

Inside the 'van I have never seen anything above 15ppm, even with the cooker in extensive use, and usually it is zero.

Thank you Vic,

Your report confirms my proposition, The 15ppm in the caravan is almost certainly due to the fixed ventilation doing its job.

 

[Thingy]

Wow, cracking topic and I read with interest the following

There is a very real danger from carbon monoxide poisoning from fumes given off by any fuel burning appliance used inside an awning or a tent.
Caravan gas appliances have flues which vent potentially lethal fumes to the outside atmosphere, and even though an awning may not be completely airtight any occupants could fall asleep and be poisoned if they used a gas heater or barbecue inside their awning. Most authoritative sources warn of the dangers of fuel burning devices inside awnings or tents, so disregard the comments highlighted in red!

However I do hold with the theory that awnings are ventilated by the very nature of what they are and think by to my days in Khaki. We used then the original Vapalux Lantern when under canvas. They are still used today, not just by the forces by organizations such as the Antarctic Expedition. We used them ourselves when camping and still occasionally do in the awning. They give a very cosy light but theres a bonus. In my experience they give off more heat than any of the halogen or fan heaters currently in use today. We never use ours in summer, but if we go early of late, its one of the first things I pack. I appreciate not everyone will approve of this suggestion but its always worked well for us.

 

[ProfJohnL]

.....

However I do hold with the theory that awnings are ventilated by the very nature of what they are and think by to my days in Khaki. We used then the original Vapalux Lantern when under canvas. They are still used today, not just by the forces by organizations such as the Antarctic Expedition. We used them ourselves when camping and still occasionally do in the awning. They give a very cosy light but theres a bonus. In my experience they give off more heat than any of the halogen or fan heaters currently in use today. We never use ours in summer, but if we go early of late, its one of the first things I pack. I appreciate not everyone will approve of this suggestion but its always worked well for us.

Hello Thingy,

Just becasue it hasn't killed you yet does not mean it's safe and without hazard. Equally it doesn't mean it hasn't affected you, you just may have put it down to other things. - Ever had a good headache or feeling woozy after few drinks in the heated awning the night before? It may just be something other the alcohol.

Awnings are generally made from high quality modern materials which are inherently more waterproof and therefore vapour more tight than the canvas used for military products you describe. Also the way an awning attaches to the caravan, and the types of zip closures do mean the top and sides of an awning will create a pretty good gas container, where as apex tents were usually rope tied which leaves some scope for natural ventilation.

The awning seal to the floor is perhaps not as tight as the top, but as the gasses were are referring to will be warm and naturally buoyant they will rise and tend to collect at the top of the awning and fill top to bottom.

The type of lantern you refer to are not particularly efficient light producers, and they do produce a lot of heat. For example a mantle uses ten times as much energy to produce the same amount of light as conventional incandescent lamp or 100 x the energy an LED lamp uses Just as a guess that would mean your lamp is using fuel at the rate of at least the equivalent of 1kW of fuel.

You may not bother about yourself, but you should think about relatives friends, and especially children who you may be exposing to dangerous fumes.

 

[Thingy]

Ever had a good headache or feeling woozy after few drinks in the heated awning the night before?

Ummmmm, yeeeeeeeessssss! Does the pope wear a funny hat? :cheer: :cheer: :cheer: :cheer:

I wish there was a sure fire way to test the safety but i do firmly believe that there is enough through flow of fresh air. Air coming in via the wheel arch and pushed out at the top through the holes for the sun shade!
True Vapalux arent efficient light producers, but the heat they give of is fantastic. We do usually have a V shaped vent open at the top of the awning all the time and that with the holes that the sun canopy poles pass through ought to be enough given the gale that hurtles in past my wheel arch cover.

That said, if you ever meet me sat on a passing cloud you can say "I told you so". Mind you, where Im going it may be a trifle warmer. :cheer:

 

[ProfJohnL]

True Vapalux arent efficient light producers, but the heat they give of is fantastic.

:woohoo:

That statement is a scientific total oxymoron. :huh: An efficient light producer will produce very little heat - like an LED for example, So a "fantastic" heat producer when you really want light makes it a very inefficient light producer.

PJL B)

 

[Hutch]

True Vapalux arent efficient light producers, but the heat they give of is fantastic.

:woohoo:

That statement is a scientific total oxymoron. :huh: An efficient light producer will produce very little heat - like an LED for example, So a "fantastic" heat producer when you really want light makes it a very inefficient light producer.

PJL B)

Prof, I think you are misreading Thingys post. I remember having a Chinese made version of the Vapalux, and Wow it was Explosive when you lit it up.

 

[Thingy]

Think prof just misread my statement. Simple mistake, I blame age

 

[ProfJohnL]

Think prof just misread my statement. Simple mistake, I blame age

OOPS - I should have gone to specksavers

 

[Anseo]

Think prof just misread my statement. Simple mistake, I blame age

OOPS - I should have gone to specksavers

I see what you did there

 

[Mel]

Before caravanning we, like many other vanners, started with a trailer tent. It had a gas kitchen which you took into the trailer tent. I believe that modern trailer tents have the same arrangement.
Clearly there have been horrid tragedies when folks have taken barbecues into tents, but there must be a safe way to burn properly serviced gas under canvas, because it is still being manufactured.
Mel

 

[ProfJohnL]

Yes Mel with proper ventilation.

 

[Hutch]

Before caravanning we, like many other vanners, started with a trailer tent. It had a gas kitchen which you took into the trailer tent. I believe that modern trailer tents have the same arrangement.
Clearly there have been horrid tragedies when folks have taken barbecues into tents, but there must be a safe way to burn properly serviced gas under canvas, because it is still being manufactured.
Mel

I think Mel has a very good point here, as we go to our local tent and trailer tent, dealer, I now remember that all of the kitchens are under cover. So must have good ventilation. And as I have mentioned before , our porch awning has permanantly open vents at the top corners.

 

[Craigyoung]

At the minute we have plenty of ventilation in our awning as my wheel is is on show as my awning skirt was damaged and ripped so I've cut it for one bit to fit the back bit behind the wheel and one bit of skirt bit in front of the wheel , went to price a new length of awning skirt , over £5o.oo !!! shocked hmy:

 

[ProfJohnL]

At the minute we have plenty of ventilation in our awning as my wheel is is on show as my awning skirt was damaged and ripped so I've cut it for one bit to fit the back bit behind the wheel and one bit of skirt bit in front of the wheel , went to price a new length of awning skirt , over £5o.oo !!! shocked hmy:

Hello Craig,
Your ripped wheel cover only provides low level ventilation. The hot fumes from what ever is burning or smouldering as in a charcoal BBQ will collect at high level where you breath.

The point about cookers in trailer tents, I remember well becasue there was a mesh window just behind the cooker.

Like it, or believe it or not the use of any burning appliance inside a tent or awning is potentially unsafe not only from teh fire hazard but also the products of combustion, which area actually more dangerous becasue you can't see or feel them.