(vi) Tents and shelter. Hidden costs in humanitarian aid and emergency. THERMAL ISOLATION.

What is the purpose of a flysheet in a tent? (Second function)

As I said before, a flysheet in a tent is supposed to offer thermal isolation for the users, but it is really hard to find a tent that has a flysheet capable to meet this expected function.

The main reason is that to make it possible to create a thermal isolation it is needed to have a physical barrier between inner fabric, the body, and outer one, the flysheet.

The purpose is that the air surrounding the tent finds something between outer side and the interior, capable of reducing the thermal transmission, in cold weather avoiding inner air being as cold as outer one and in hot weather avoiding inner air being as hot as outer one.

In architecture and construction, in a simplified manner, there have been historically three main ways to reach this goal: first very effective way was to make a thick barrier, sometimes even one meter wide; second way adopted, not so effectively, was to reduce this thick walls in order to save money in the house building substituting it with lighter materials and using inner layers of isolation materials and leaving some space for creating an air barrier, and finally it was discovered that one third effective way to create a chamber of air in movement, between inner air and outer air, keeping this air chamber between two layers of material. This is the effect known as ‘ventilated façade’.

 

The ventilated façade works as follows:

When the sun shines, the air inside the chamber is heated and it starts to flow to upper areas. As the hot air goes up, fresh air occupies the space abandoned by hot air, bringing fresh air inside the air chamber, if the hot air has an escape way to flow to the atmosphere, this movement becomes continuous and the flow of air avoids the inner air inside the tent getting hotter.

The outer layer that creates the outer closing side of the barrier also avoids the sun to impact directly on the inner body and helps also, in this way, to reduce the inner temperature.

The air barrier between outer layer and inner layer creates a difference, a gradient, of temperatures, keeping the interior fresh.

When the weather is cold outside, the same effect is produced. But with some differences: If the hottest air is not allowed to escape the air chamber, the air inside the chamber maintains a higher temperature than interior and avoids the interior to lose temperature. In this way, the air inside the chamber is a barrier that avoids inner air to cool too much.

When we analyze most tents in the market, we can easily find that the immense majority of tents have a flabby flysheet (those which have one) that is not capable to be tightly separated from inner body, even many of them commonly touch frequently the inner layer. This kind of flysheets are not capable of keeping an air chamber functioning.

To have a real air chamber capable of producing thermal isolation it is needed to have inner and outer layer permanently separated. Otherwise, the free circulation of the air inside the chamber would be obstructed and the air chamber wouldn’t work.

To have a tight flysheet separated of the inner layer and to keep both layers stretched permanently it is not an easy task. Ctents is a tent that shows that it is possible to create a ventilated façade effect for a tent.

If you liked this article, please recommend it to a friend, thanks! Please leave your feedback.

(v) Tents and shelter. Hidden costs in humanitarian aid and emergency. PROTECTION OF USERS.

What is the purpose of a flysheet in a tent?


A flysheet in a tent has a double function:

1) Protect the inner body of the tent of being directly exposed to the inclement weather.
2) Offer thermal isolation for the users.



First function is the most known one, but it is really hard to find a tent that has a flysheet capable to meet the second. In spite of that, quite a few tents do not satisfy well at all the first.

Why not? 

Take a break to leave me your feedback.

The reason is very simple: A flysheet is like a roof in a house. Can any of us imagine a roof in house that is not well fixed and that does not maintain its shape when the wind blows or rain, hail or snow falls? Of course not!, nobody would think in building a house where the roof can easily move, making waves and forming pockets where the water can accumulate and produce leakages in the interior.



This appears to be obvious for a house, but, why it is not so for a tent?

It is common to find tents that have a flysheet that works more or less well when it rains... not intensely, but it is very easy also to find many tents that have a so called flysheet that easily get loose when the wind blows or the rain drops heavily, and it is quite difficult to find many capable of standing well a hailstorm. In fact, in these cases, this piece of fabric cannot be called properly a ‘flysheet’, but just a ‘second fabric layer over the tent’ with mostly a psychological function for users.

To have a flysheet in these tents working effectively it is necessary that users keep themselves very aware of weather, in order to quickly readjust the tensors of the flysheet as soon it is not stretched enough and also they have to be very careful to avoid touching inner layer as they could connect the inner to the outer layer provoking a leakage. In fact it is not very comfortable to go camping and to have to suffer these unpleasant jobs in the middle of the storm instead of feeling protected inside.

To put things clear: In order to have a flysheet that really performs its first function, it has to keep stretched tight under inclement weather conditions (when it is really expected to perform its function), but traditional constructive solutions for tents do not solve this problem without the careful monitoring of the users, ready to tight the guy-ropes and tensors when the flysheet begins getting too loose.

To solve this question the trick is going back to the concept; to understand well what this piece of fabric is intended for, and then, to design it in such a way that really works as expected. Without human intervention!

Otherwise we, as designers and manufacturers, will not be offering to the users what they need: A reliable tent that takes care of them when the weather is not an ally.

Next week I will talk about the forgotten one by most of the manufacturers, the second function of a flysheet.

Please leave me your feedback.

If you liked this article, please recommend it to a friend, thanks!

(iv) Tents and shelter. Hidden costs in humanitarian aid and emergency. TRANSPORT & STORAGE.

Is it just the price of the emergency tent the only important thing for taking the right decision when selecting a tent for emergency brigades?

When a buying decision has to be made, it is important to consider all its implications. To buy a tent is not just a matter of choosing anyone, like when one goes to the pastry shop, looks at the pastries and selects one for its shape, colour or by its expected taste.

For rightly selecting a tent the thing is something a bit more complex.

When a tent is going to be used in a future, and is not yet clear to what country or climate it will have to travel, and it is not clear either if it is going to be used just for people of one sex or both, if it is going to be used in a place where it is going to rain a lot or, instead, in a dry one, and the tent will have to spend part of its life stored in a warehouse waiting for an emergency to arise, and then be shipped quickly to a distant country where it is going to be useful for someone, then, the selection of the tent should take into consideration the different possibilities. 

The tent to be stored should include every element that could be needed at the emergency site, 

for instance, inner separating curtains, flysheet, floor, and others.

To store a tent should be done in an easy way, having packages easy to carry by hand and that can be stacked in order to minimize the warehousing space, and therefore reduce costs, and also making it easy to find the correct package when needed.

As all we know, when the emergency situation happens, there is no much time left to think and debate, is time to act fast, in order to help as soon as possible those who happen to be in the middle of the human drama.

Someone is going to pick up the needed tents from the warehouse and to prepare a shipment to the emergency site, the first shipments usually by plane. This person maybe do not knows anything about tents. At that moment it becomes critical to ensure that all the packages corresponding to the same emergency tent are shipped together and that the possibilities for them to be separated from each other are reduced to a minimum..., and that should be done with the minimum effort and minimun knowledge needed!

The tents will usually be loaded in a truck where the use of space is crucial, it should be possible filling the truck completely (without overload it) and then transfer the packages to the corresponding aircraft hold. At this time, it is also critical - before, it already was - the weight to be transported, as every kilo in an airplane counts a lot. To send an airplane plenty of emergency material is not cheap, to be able to send as much material as needed with the minimun weight, is a must.

For the above reasons a tent should be designed having in mind all these factors:

1) Minimun weight for maximun useful tent surface

2) Simple packaging including all the pieces that can be needed in different emergency situations

3) Better 1 package for a tent than 2 or more, as more packages, more easy to mislay one or to lose it completely. When one of the packages is not there at the emergency site, the rest of the tent can become unuseful.

4) Package shape should be as much as possible like a parallelepiped in order to there are no hollows left in the truck or in the aircraft. The rental of the plane, specially is going to cost mainly for the plane itself, so, in some manner we could be paying for transporting hollows, plenty of air, and, of course, we should avoid that happening.

5) As the tents are going to pass from one place to another, and usually not small quantities of them, the best way to carry a number of them, to fill the aircraft hold or to offload it, is with a forklift, but the best way to transport load with a forklift is within pallets. The best thing should be that the tents had pallet like size, in order to the load is distributed uniformly and organized adequately.

6) Each tent should be as easy as possible to be carried by human beings, as they are the ones who will put them in place at the emergency site before the tents are assembled.

To summarize, the big issues for pakaging and transport are:

• Minimum specific weight kg/m2 of useful surface
• Every element needed included in the package
• 1 package for each tent
• Package with parallelepiped shape
• Package dimensions compatible with international standard pallet size in order to fill it completely
• Easiness of carrying.

One of the things most surprised us when we began to work on this aspects of tents design, is that most of the manufacturers have ignored these seemingly obvious criteria, if anyone has consider it!

If you liked this article, please recommend it to a friend, thanks! Please leave your feedback.

(iii) Tents and shelter. Hidden costs in humanitarian aid and emergency. ASSEMBLY

Is it just the price of the emergency tent the only important thing for taking the right decision when selecting a tent for emergency brigades?

3. HOW IMPORTANT IS THE EASINESS OF ASSEMBLY OF AN EMERGENCY TENT?

Emergency aid activity is not a matter of money in the sense of money that can be produced by the people working on it, but it does not mean that the money or the hidden cost is not something important for the emergency activity.

How can influence in the cost of using a tent the assembly time and the people needed to assemble it?

This is the question that I am going to try to answer today.

The emergency, of course, is a matter of productivity, of urgent productivity!! It is important to be able to serve as many urgently needed of assistance people as you can in the shortest period of time, for instance when searching for victims of an earthquake under the debris of collapsed buildings.

Productivity of emergency services is something associated with persons, the persons at the emergency aid side, persons who must be ready to work hardly, so it is important for them using their time effectively. In such a context, it is important to reduce to the minimum necessary the auxiliary activities like the one of putting on a tent or caring about it in order to have the tent ready to use. All that can be done to ease the job of emergency brigades is going to improve their productivity and their capacity of concentration and to avoid annoying distractions that can disturb their work.

To set up an emergency tent would be nice if it could be done in a 'pop up' way just like modern individual tents can, but for big size tents - big enough to give adequate service to emergency brigades, as dormitory, canteen, command tent or others - it is something that has not been made possible yet. And I personally do not recommend a pop up one.

There are many manufacturers that are aware of that need and do their best to improve assembly time. But there is a difference between being aware and being committed to. Very frequently the real world is a bit apart from the manufacturer's specifications!

When you see that a tent it is claimed to be assembled in 3 minutes, it is important to know what period of time these 3 minutes are referring to and how much people is needed in the operation.

When it is a matter of assembly just one tent, it may be not so important, but as the number of tents increases the assembly time starts to become important and even crucial.

To be able of comparing the assembly time associated to different tents, it is important to have a truly comparative unit. The most common is to compare a rule of thumb. But the mistakes made can be quite big. Even it is scarcely used, there is only one possible unit that can be used to make real comparisons: The unit to be considered is the man-hour or man-minute for shorter operations.

Of course is not the same A) to assemble a tent in 5 minutes, with 4 people that B) to assemble one in 8 minutes, with 2 people. In the case A) in fact 5x4=20 minutes-man are needed to assemble the tent while in B) 8x2=16 minutes are needed: 4 minutes less, a 20% of time less than in case A)!!

But why it is important also to refer to the same period of time? The time for tent's assembly should be considered from the moment it is going to be placed at the site where it is going to be set up to the moment when the tent is ready for use.

Some tents are very heavy and they need to be carried by four strong man or more, or even by a forklift to be placed on the site. Once again, it is not the same thing to carry over a 100 m distance two tents, of same size and for same use, one being carried by 4 people and the other only by 2. And, of course, it is quite different to have a tent that can be carried inside just one bag, or to have two or three packages to carry. As more packages you have, the more time consumed in bringing them to the place where the tent is going to be used.

One more thing to be considered is the unpacking of the tent, it is not the same to have several packages that having only one, and it is not the same to have a easy to access boxlike package that to have one with a narrow hole through where to extract all the pieces of the tent. All these simple operations are time consuming and they need persons who performed them, so a wise way to compare the assembly time of several tents is to count all these operations in man-minute unit basis and then compare the final figures. It can led to a nasty surprise for you when you compare the assembly time stated by a manufacturer and the real time needed.

It is important the time needed to place every part of the tent in the right place in order to have them ready to be assembled.

Finally, it is not less important to consider how many tools are needed and how small the pieces are, as the smaller pieces in the package are, the easier to lose some of them while assembling the tent; as more tools or machinery needed, more possibilities of loosing some, not finding them at the right place, or breaking a tool. In case of fuel fed machinery it is also important to consider the inconveniences of fuel supplying.

It is not negligible the time to disassemble the tent and to pack it, sometimes the choice is to leave the tent there, but not always is the one desired.

MY CONCLUSSIONS ARE:

1) To be sure of how much time is consumed in an emergency tent assembly, it is necessary to consider:

i) Man-minutes to carry the tent package over a standard distance, 100 m for instance.
ii) Man-minutes to unpack the tent pieces and place them at the right position to easy the assembly
iii) Man-minutes to prepare and have ready the auxiliary machinery for assembly
iv) Man-minutes to assembly the tent.

2) The cost in man-minutes, or man-hours, is a non recoverable cost: When you lose time at the emergency site, you cannot recover it anymore, so, either you use more people for same tasks, or you reduce the time used in aiding victims.

3) Some hidden costs difficult of being evaluated are the cost of loosing tools or breaking them or the cost of loosing small pieces of the tent that must be substituted by improvised pieces not so efficient as original ones.

Next: Transport...

Please leave your feedback.

(ii) Tents and shelter. Hidden costs in humanitarian aid and emergency. MAINTENANCE

Is it just the price of the emergency tent the only important thing for taking the right decision when selecting a tent for emergency brigades?

2. SHOULD A TENT KEEP ITS SHAPE WITHOUT HUMAN INTERVENTION? WHY NOT?

Are tent manufacturers always aware that emergency brigades and volunteers in humanitarian or emergency aid are also persons? Persons who need to have a rest after a long and strenuous journey.

They should not have to start another new job when they are going to use their temporary housing, the task of keeping the tent tight.

What if someone tought in advance in make it easier for these so sacrified and encouraging people their own living at their temporary housing?

When we look at the market we find many tent manufacturers, each of them offer 'their' own solution, but it is really hard to find some that offer not their solution but the solution of the people who is on site putting their best efforts to help damnified homeless people, to save lives, to help rejoining broken families (when possible), to organize the disaster after the catastrophe arises...

When you talk to the people who has been to the site for so many times in thier lives that they are not able to count them, you inmediately understand why they dislike so much inflatable tents, they like of course to put up their tents in few minutes, but... 

They don't want to become slaves of their temporary housing!, having to inflate and deinflate it several times a day, day after day, why?, because the outside temperature has the bad habit of changing without respecting the theoretical assumptions of tent designers.

High daytime temperatures and low temperatures at night makes the pressure of the tent vary and then it oblies to inflate the tent at night when the pressure is low and deinflate it at the middle of the day when the pressure is high.

It is not only the time spent on these annoying tasks but the noise produced by the compressor machine and the need of fueling it, and having a reserve of fuel or looking for it in the worst conditions. The emergency brigades or volunteers are not expected to devote their precious time to this intendence tasks or to be disturbed while resting at their tents by a disturbing noise when the compressor machine starts to run.

Is then the solution a traditional tent with its guy ropes? Not really, the experience shows that this kind of tents need to be adjusted also very frequently, particularly when the wind blows or the rain falls.

But, then, what is the solution for having the tent erected without devoting time to this task?

This is one of the main ideas to have in mind: A tent should be capable of keeping its shape without making it necessary to have some people tighting the tent or adequating the inside pressure. Let's free the users so they have more time to devote to the task they are there for.

Next: Assembly


If you have liked this article, please recommend it to a friend, thanks!

Please leave your feedback.

Tents and shelter. Hidden costs in humanitarian aid and emergency. SPACE.

Is it just the price of the emergency tent the only important thing for taking the right decision when selecting a tent for emergency brigades?



1. THE SPACE, FIRST THING NEEDED TO ENJOY A PRACTICAL COMFORT.

When an emergency arises, there is no much time left to spend in selecting the right tent. Nor for victims neither for professionals or volunteers helping them.

The emergency tent selection is like so many other things in emergency management: What makes the difference is the planification and preparedness.

One of the most important things for the people who is being on site for emergencies lasting more than a couple of days  is to have a place to sleep where it is possible to rest for a while.

It would be fine to have a nice and comfortable place, with a bed and enough space around in a solid building where to spend the resting ours trying to sleep, but this is not usually possible.

For most of the people on emergency site, the tent is the only available solution.

Tents were invented more than 20 centuries ago, the problem is that most of them still are quite similar to those of the first years.

The first consideration for having a practical comfort in a tent is having enough space, inside and at the surrounding space. We are use to see a messy labyrinth of guy ropes crossing all the free space between tents in an emergency campsite, making it difficult to move around to the people who have other major concerns at that moment. To make easier their lives letting them free to move around without obstacles crossing their path should be one main objective for a high quality tent designer.


When a volunteer or an emergency proffesional after a hard work journey, lasting sometimes for 24 or 48 hours, need to have a rest, we should help to him or her to enjoy a practical comfort in their temporary sleeping sites. If you ever tried it, you will know that one of most annoying things is when you have to put on or take off your trousers while sitting on the floor with your legs up, you rather would prefer to be able to stand up inside your tent. That should be a second major concern: Create a inner space spacious enough to move freely and make it easy to enter into and exit from this space.

To be continued...



If you liked it, please recommend it to a friend, thanks!

Please leave your feedback.