Related to MAKE 05, MakeShift
MakeShift 05: Erik Brown's "Emile Gagnan" Honorable Mention
by William Lidwell
July 07, 2006
What can I say? I picked Erik to be one of the winners, but Woody had the final say and awarded him an honorable mention. Woody comments: “Mr. Brown was very methodical and creative in tackling the problem and came pretty close. This was such a touch decision. Loved the quantitative approach and illustrations.” Congratulations Erik!
The "Stuck in the Vault" problem has many potential solutions, ranging from electrolyzing the water in the water cooler to using the water jug and come chemicals as a CO2 scrubber. But all the solutions I thought of relied to a certain extent on the specifics of the situation and the actual materials involved (e.g., the size of the vault, the quantities/sizes of all the materials you have on hand--wire, tape, length/diameter of garden hose, etc.). As such, if I were really stuck in this situation, I would look into the feasibility of several different solutions before deciding on one. However, in all my solutions, the first step is to take out 4-8 paper cups and fill them with water from the water cooler and set the cups on the desk. Depending on the size of the cup, I assume I will need around 2-4 cups of water per day to avoid major dehydration problems.
The first approach to the problem is to spend a good 10-15 minutes looking throughout the room for some kind of "emergency" release lock. One would hope that a conscientious vault designer would build in this sort of device to solve the exact problem I am facing. The vault company might get in big trouble if someone died inside their product from this kind of situation. If Woody could easily lock me in, it is conceivable that someone could fairly easily get locked in accidentally.
If I couldn't find any sort of emergency release, I would then try to assess whether the vault was "air tight," other than the 3/4" vent tube. The picture of the vault door in Make magazine makes it appear as though there may be a slight gap underneath the door, or perhaps I could find some cracks/crevices on the wall that suggest that the room is not airtight. If the vault is not airtight, than the solution is to simply set up a flow-through system where I breath air in from the room, and out through the garden hose which I hook up to the 3/4" vent tube. If I cap the garden hose each time I breathe in, I will suck fresh air into the room and exhale all the CO2. In addition, I could make this solution a little simpler for myself if I made a "gas mask" out of the paper cups that had two one-way valves, one only allowing room air in, and the other only allowing the exhaled air to go up the garden hose. This solution would keep the CO2 and O2 levels at normal conditions in the room (assuming that the air being sucked into the room was "normal" air).
If I conclude that the room is airtight, then I would investigate the vent tube much more closely. Using the steel cable, yard stick, and possibly ripping one of the emergency lights off the wall for a makeshift flashlight, I would try to determine if the vent tube leads to a ventilation duct fairly near by, which may have flowing air through it. Depending on what I find (Can I hear moving air? Can I see anything? If I slide the steel cable up the tube, does it feel like it reaches a large open space? etc.), the next possible solution is to create a circulation system through the vent tube.
If the vent tube leads to a nearby duct with moving air, I can stick the yard stick up the vent (with it's width trimmed down using the pocket knife, if necessary) into the duct, and by rotating the width of the stick until it is perpendicular to the air flow direction, channel flowing air down 1/2 of the vent tube into the vault. This will create two flow paths with a semi-circular cross-section in the vent tube, one bringing air into the room, the other bringing air out of the room. This flow path could also be done more effectively using a modified length of garden hose, if the hose's diameter is small enough to fit into the vent tube and allow space in the vent tube for a return air path.
After inserting the yardstick/hose into the vent, if the air flow into the room is significant, this may be enough flow to provide plenty of fresh O2 and keep the CO2 concentration at a safe level. If the air flow into the room is only very light, then I would set up a system where I breathe from the side of the circulation system that provides fresh air through the hose, and exhale out into the room. If, however, my exploration of the vent tube suggested that it may be a very long 3/4" tube in which it would be impossible to set up a circulation system, my next approach would be to pray.
I would pray that Woody was nice, wasn't interested in going to jail for manslaughter, and that he would realize fairly quickly that he should probably try to help me out. One thought would be for him to drill a small hole through the vent door to allow me to get fresh air...Once the vault doors close, it may not be able to be opened for 48 hours, but I am fairly certain that a small hole could be drilled through the door.
After praying for a few minutes, my next thought would be to look into setting up some kind of CO2 scrubber. Based on the supply list, the best approach I came up with is to set up a system where I breathe into the water jug through a section of hose, and both the water + some other chemicals I add capture the CO2. From the supply list, the only thing I think might help is the chalk in the chalk-line reel. This chalk is mainly CaCO3, which will combine with equal parts of CO2 and water in the following equation to absorb some CO2: CaCO3 + CO2 + H2O -> Ca2+ + 2HCO3-
The problem is that to survive 48 hours, and assuming I can survive 24 hours before the CO2 levels are toxic, I need this CO2 filter to absorb the amount of CO2 that I produce in a day, which is roughly 1000 grams or approximately 20 moles. This would mean that I need at least 20 moles of CaCO3, which is about 5 lbs. worth. If the chalk-line reel is large enough to contain 5 lbs. worth (doubtful), this solution may be worth trying, but it also depends on the size of the room because while the O2 levels may not become deadly in 24 hours, they may reach hazardous levels in 24-48 hours.
If all these other avenues were unworkable for some reason and I was somewhat concerned about my O2 supply (again, depending on the size of the vault), I would create a solution wherein I would preserve as much of the O2 in the room as possible while at the same time expelling all of the CO2 from the room. In order to actually expel the CO2 from the room, I need some kind of flow-through system, and fortunately, I have a very big jug of water which can be evaporated or electrolysized to produce the gas necessary for such a flow system. The following diagram (click on the thumbnail) shows my proposed set-up:
The way this system works is that 1) I take a breath in from the room, 2) I breathe into the Diaphragm Bag for 3-4 breaths (approximately 30 seconds total - the bag is used just like a paper bag for someone who is hyperventilating), then, after sucking out all the air in the Diaphragm Bag, I expel the air into the One-Way Valve Face Mask. This will push the CO2 laden air from my lungs into the Vent System that travels directly to the 3/4" vent tube. While all of this is going on, the water in the large water jug from the water cooler is being either electrolysized (using the wire and leads from the emergency lighting battery recharge system) or is being heated/evaporated by the resistive heating element that I either removed from the water cooler or made using the steel cable and some wires from the water cooler. The electrolysis/heating element will generate the gas (either H2 + O2 gas or steam) to allow the CO2 to be pushed up the garden hose and out of the room. Without such a system, I would just continue to re-circulate the same air in the room...At the same time I expel the air into the One-Way Valve Face Mask, I lift-up the edge of a piece of tape covering a small vent on the water jug. This will bring approximately 1 liter of steam or H2+02 to replace the volume of air that I am pushing out of the room. As soon as I stop exhaling into the One-Way Valve Face Mask, I close the vent hole in the water jug with the tape, take a breath from the room, and breathe into the Diaphragm Bag again, all the while breathing like I am enjoying a nice, beautiful sunset. This cycle continues for 48 hours. However, luckily, my work is not done yet.
In order for this system to work optimally, I need to ensure that the water is not being evaporated/electrolysized either too quickly or too slowly. The minimum rate would be to match the rate at which I exhale air into the One-Way Valve Face Mask, or approximately 2 Liters of gas produced each minute. The maximum - for the evaporation route at least- would be around 8 liters of gas produced each minute. At 8 liters of H20 steam per minute, the 5 gallon jug will be emptied in approximately 48 hours (ignoring the condensate that would constantly be forming and falling back into the tank). Unfortunately, determining how quickly the gas is being produced is challenging. The first challenge is knowing the time...A clock wasn’t on the Supply List, but I always wear a watch, or perhaps the phone on the desk has a clock, or my cell phone has a clock, or in a worst case scenario, I could make a timer using paper cups lined with electrical tape that have a small hole at the base and measure the time it takes for that cup filled with water to completely drain out of hole, and I would count the time with my at-rest pulse rate (70 beats per minute) - so if it took 70 beats to drain, I would know that the cup was a decent 1 minute timer. Using one of these timers, I would measure the rate at which water was being lost from the jug. My target would be to remove around 1/8 of one gallon every two hours. This corresponds to roughly 1/40th of the 5 gallon jug every two hours, so I would mark the level of the water, and based on the 5 gallon level mark (if the jug was not filled all the way), mark notches on the jug with the pocket knife that correspond to 1/2, 1/4, 1/8, etc all the way up to 1/32 of the jug. Using these lines and my timer, I would measure how quickly the water was leaving the jug and adjust the system to remove 1/40th of the jug every two hours.
In terms of whether to use the electrolysis system or the evaporation system, I would first experiment with electrolysis system as it would donate some O2 to the room. However, considering the energy requirements of electrolysis and the fact that I may or may not have all the right components (good electrodes, access to the right kind of electrolyte - like sulfuric acid - which *may* be available in the emergency lighting batteries, wire that can handle the rather large amperage that electroysis which produces so much O2 and H2 would require, etc.), I think that the evaporation approach is likely going to be the more successful one.
In terms of construction, the only device which is a little time consuming to make is the Diaphragm Bag. The simplest approach is to use a plastic bag which the workers may have left behind, but another option is to construct the bag out of flattened pieces of cut-up-paper cups. Just cut off the base of the paper cups, flatten them, and tape the edges together to form a sheet. Make two roughly square sheets the size of a regular piece of paper, tape the edges together to form a pocket, cut a small section of hose for the mouthpiece, and seal the whole thing with more tape. See the diagram below (click on the thumbnail) for the general appearance.
So, with all these pieces at work, this system should keep me alive for 48 hours or more (see Appendix for calculations). After all the set-up work is done and I have 40 or so hours to kill, I would hopefully still have enough energy to continue modifying and improving the system as a whole (40 hours is LONG time), and I may just begin considering how I am going to repay Woody for these wonderful two days once I get out... :)
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