Reefer Slab – Plumbed and Insulated for Pour
Flowable Fill that is. Due to a communication error we got a type of concrete I wasn’t quite expecting. Instead of slab concrete we received a truck load of what is termed Flowable Fill. Fortunately the pump truck operator caught the error before it was spread on our reefer floor. I diverted it to something else. Not ideal but a way of making use of a bad situation before it got worse. Sometimes you just have to go with the flow. And man, does flowable fill flow. The stuff comes out almost like water. It is very close to self-leveling, but not quite. Unfortunately it only has a strength of about 300 PSI which is insufficient for the reefer’s inner slab.
Our facility is built like a thermos bottle. A thermos bottle within a thermos bottle within a thermos bottle, in fact. The outer most bottle is the outer shell of the building. That outer shell stops the sun and floats at the ambient temperature. Inside of that is insulation and then the structural shell of the building. This will float at about the annual median temperature which is approximately 50°F. That is what we’ve been building up until recently. This spring we began building the refrigerated section, the reefer, which is an insulated box within the northern two thirds of the building. Cool things happen there.
The reefer is thermally isolated from the 50°F structural building and divided up into a number of smaller rooms that get progressively more isolated and colder. Because it is starting with an environment of 50°F, the structural shell, it is easy to get the large mass of the reefer down one more step to below 41°F which are typical refrigeration temperatures. This means we have a refrigerator that is a bit over 7,500 cubic-feet. That’s a heck of a lot bigger than our current 25 cu-ft chest freezer!
So our pour for today was the slab of this inner area – the reefer slab which will float below 41°F. It’s a big thermos bottle.
Hope Perforating Bronchia Tubes
The next two trucks of concrete were what we needed: “Commercial Grade 3000 PSI with Super Plasticizer and Fiber at a Slump of 9 inches”. That is still a very wet mix. The reason we needed such a flowable concrete, as self-leveling as possible, is the reefer is filled with plumbing and access tubes such that it makes screed boarding to level impossible. Instead what we did was to use the marks on the walls and pipe heights to get it as close as possible with rakes and pullers. After we have poured the reefer inner walls we will then be able to setup screed boards and level to the floor drains with just a slight tilt of 1/4″ per linear foot. With such small rooms this will be easy to achieve.
The past month has been a huge amount of prep-work for this pour. We had to get layers of plumbing at multiple altitudes for six rooms all draining right, insulation, access ports, the reefer lungs and self-chilling system, more insulation and sealed so concrete won’t leak in, iron work (rebar) and welded-wire mesh all in place. This was our most complicated pour. The other upcoming sections of the building in the administration and abattoir will feel like a breeze in comparison. In addition to doing the reefer we also poured in the lairage – the holding area for animals the night before slaughter.
The plumbing is very complex and there is a lot of it. After I got it all designed Will and I cut all the pieces, fitted them together loosely and checked the layout. Then I coded the entire system so we could take it all apart and know how to put it back together correctly while we were solvent gluing it for the final fit. I used up four and a half alphabets.
Will Studies Writing on the Wall
As we work I write a lot of notes on the walls to keep track of what’s happening. Cut lists of pipe lengths and diameters. Sequence to-do lists. Check lists. We also keep a set of plans up on the wall with the latest revisions. Traditionally they are called blueprints but I do mine in full-color to get extra meaning in every layer.
Ben a’Puzzling – Trachia & Bronchia of Lungs (green) in Foreground
Where possible we use large 4’x8′ sheets of 2″ pink foam to build up the floor insulation under the reefer. But with the varying altitudes of the pipes this is not always possible. Sometimes it needs just 1/2″. Sometimes 1″. Sometimes 1.5″. In the picture above Ben is using scraps of insulation to create a jig saw puzzle of tightly packed pieces around the plumbing. Then he can-o-foamed it with expanding foam. When we got all done doing all the plumbing and fitting we sealed all of the pieces of foam together and to the walls to create a mold for the coming concrete.
Not all of the PVC piping is plumbing for water. Some of it is part of the lungs for the reefer that allow us to use natural drying air currents to keep our insulation in top form and cold using winter’s air. A lot of the other pipes are accesses for probes and inspection points to the various layers of the flooring and insulation so that I can monitor the system under the different rooms, each of which has its own temperature zone. This is not just a production facility but a research space into some of my ideas on low energy construction. As such I want to be able to get in and look at things, stick probes in, etc.
That funny pink boxy area in front of the kids is the plumbing trench which gives us straight line access to almost all of the plumbing lines for clean outs in addition to the various clean outs in the poured area. You might notice in some of the later photos that the box of pink foam is cut down to its final size leaving the inner box of plywood that keeps the concrete out of the plumbing access trench. This made a mold for the concrete around the trench.
The inner box of the reefer is a building all in its own right that is thermally isolated from the outside world by a thick layer of insulation to minimize the transfer of heat and save energy. But at doorways and the plumbing trench we have a thin connection between the reefer and the outside structure. Since I don’t want the 126,000 pound reefer settling downward a half inch and severing electrical lines or other things there are several pillars spaced around the structural beams of the inner reefer to support the weight. This tube penetrates the foam layer and provided a path for concrete to flow down to the lower slab. We’ll get a very small of heat leakage across this interface but that is better than settling of the inner structure. Theoretically the foam layer should hold over three million pounds of weight but who wants to risk it. Besides, in a thousand years the insulation may evaporate – it’s organic and plastic doesn’t last forever.
Unlike the pillars, the plumbing and access points need to not have concrete flow into them during the pour. Ben discovered that can-of-foam lids make perfect caps for 2″ PVC pipes to keep the concrete out of the ends. This makes it easier to get out test plugs. Not only do they fit just right but they’re bright yellow making them highly visible so we’re not as likely to bump them or trip on all of those pipes. For the 4″ pipe we used five pound cottage cheese pails – plain white unfortunately.
We had a little more foam than we needed for this layer so we hung the extra up along the north wall to get it out of our way. The “extra” will get used isolating the freezer and cooler from the reefer. Bottles within bottles.
One of the last things we did was install rebar along all the beams of the slab and then 661010 welded wire mesh across the entire slab to be poured. Vertical pieces of rebar are setup to attach the future walls. Ben and Will have gotten very good at cutting and bending rebar in addition to their other carpentry skills. I just give them cut plans and they’re off.
You’ll notice there are a lot of stones below the wires. These hold the wires up off of the pink foam so that even when we walk on it the wires bounce back up into the concrete to the height I want them at. Our slaughterhouse and butcher shop make extensive use of Vermont granite.
The blue sill wrap is to protect the PVC pipes from the steelwork.
To the right you can see the outgoing trachia and a vertical rebar as well. This shot is over in the chiller by the doorway coming from the abattoir.
At some point in your life some joker has probably asked you to go get a skyhook. Well, Virginia, there really is a thing and it is quite wonderful. A pump truck makes placing concrete a lot easier.
Will Vibrating and Leveling – Walter Guiding
It makes it so we can get done with our small crew what would otherwise take a big crew or just not get done. Pump trucks are expensive but worth the cost. Shh… Don’t tell Scott Ireland – owner of S. D. Ireland who supplies our concrete and pump trucks. Just kidding, he’s a great guy.
View of Pump Truck and Concrete Truck from North
Notice the pink concrete truck that has pulled up to the left on the road and is waiting its turn to dump into the hopper of the pumper truck.
The slab is poured. I have purposefully left it rough because we’ll be setting up forms on top of this slab to sub-divide the reefer into the carcass chiller, raw cutting room and sausage making room, RTE kitchen, brine room, cooler and freezer. By leaving it rough the walls and final floor can grab onto this concrete. All of the partitions will be made of concrete – no wood in the final building. Once the walls are in place then we can do the final floors that will be screedable over the tops of the floor drains and cleanouts which we’ll be cut to height by then.
In an ideal world we would get exactly the amount of concrete we need but it is very difficult with irregular shapes, think of all that plumbing, to calculate exactly what is required plus some gets lost in the pump truck. The solution is to order a little overage and have a plan for how to use it.
When estimating concrete it is far, far better to be a little over than at all under. I was over so we had the pump truck operator place a pad of concrete in a stone walled area around the north whey trough. This makes it so the pigs aren’t standing in the mud by the trough, gives better drainage and it trims their toenails automatically. I place stone around eating and drinking areas as well as on trails so that the ground doesn’t get as worn and the animals nails get trimmed. This saves me from having to clip nails for three hundred pigs, sheep, etc. No need to work harder than necessary.
Outdoors: 84°F/56°F Sunny
Tiny Cottage: 78°F/64°F
Daily Spark: “Success is not final, failure is not fatal: it is the courage to continue that counts.” -Winston Churchill