Residential septic tanks are available in 1,000, 1,500, and 2,000 gallon sizes. Builders routinely install a 1,000-gallon tank. Two 2,000 gallon tanks are better: one connected only to toilets for sanitary material, and the other connected to everything else for “gray water,” each with independent leach fields, each leach field having 50-100% greater capacity than required for the projected load. (Research “septic system distribution boxes”.) Building plumbing should be designed to allow sanitary-only piping to be easily reconnected to the gray water piping in the event of sanitary system leach field failure.
Toilets should be cleaned only with isopropyl alcohol, not commercially available toilet cleaners, and the alcohol burned in the toilet rather than flushed. The only thing going into the sanitary septic tank should be liquid and solid sanitary waste, no soaps, detergents, or chemicals of any kind; all of that will kill the bacteria that digests the solid waste, resulting in faster accumulation of solid waste and shortening the time between pumpings. Periodic infusions of brewer’s yeast will aid in digestion of waste material in the tank. Tank should still be pumped out periodically, because digestion process is not 100% effective. The pump-out cycle will be dependent on sanitary system usage volume.
A gray water septic tank should be accessible to allow access to the gray water; some plants (example: roses) prefer slightly alkaline water. No greases or oils of any kind, especially cooking oils and animal fats, should be introduced to either tank. Oils and fats are lighter than water and float on the water in the tank, making them the first liquids that are carried out into the leach field; oils and fats eventually clog the pores of the soil, and it stops absorbing liquids, requiring the digging and installation of a new leach field. The gray water tank should never need pumping, unless sanitary leach field failure requires connecting sanitary piping to it.
Codes will almost certainly require a commercial building above a minimum size to include a fire sprinkler system. Plan for the water demands of that system, especially on the lower floors. Using a public water system during “happy path” period is fine, but if no public pressurized water is available, the building can be easily destroyed by fire to drive occupants out. All construction on the lower floors should be of absolutely fireproof materials and extremely limited use made of flammable furniture and fixtures. All internal water systems should be “heavily valved” to allow full control of every major and minor subsection of the water system. (Research “submarine piping and control valve layouts”.)
Fire resistance should extend to the roof structure and material. If bandits can’t burn you out from below, they’ll launch combustibles onto the roof. Hurricane glass in windows accessible to bandits or mobs, while expensive, will keep thrown missles out of the structure; a bonding security film should also be applied to the interior of the glass. (Research “3M security film”.)
A means should be included to allow “repelling boarders” who attempt to gain access to upper floors with ladders, cherry-picker trucks, et cetera. The easiest method will be gunfire, but there are other less attention-getting methods, including flame thrower ports, flammable liquids and flare pistols, tear gas nozzles on the exterior, et cetera.
During construction, tunnels should be included to allow for potential escape and provide a path to well hidden strong points out to, and beyond, the “legal” perimeter. (“Legal” is referring to land owned and controlled by the entity that owns the structure.) Unless there is overwatch available capable of defending the exterior of the structure, it will always be vulnerable. It is quite effective when attackers suddenly have lethal threats “magically” appearing behind them.
All landscaping should be done to prevent vehicle access within a defensible perimeter, short (3-4 ft) positive terraces farther out and negative terraces closer in do that well. If designed to deter HUMMVs, it will stop anything with wheels short of “monster trucks”. Angle of departure restrictions prevent wheeled vehicles climbing the wall, the drop-offs on negative terraces will high-center and “nose lock” vehicles attempting to negotiate the obstacle. Negative terraces also eliminate a place for attackers to hide or be protected during attack. All terrace wall construction should include piping to allow future use of anti-personnel devices. (Research “fougasse design and construction”, especially application and ignition of flammable liquids.)
Tracked vehicles can more easily overcome (or destroy) barriers, so your AO (area of operation) intelligence should include constant awareness of any heavy construction equipment within several miles, and operations should include a means of destroying it. The structure should include secure storage for utility vehicles and their required fuel. A small bulldozer and a medium tractor with front loader and backhoe can be extremely useful and accomplish in a couple hours what it would take 20+ men a day or more to accomplish by hand.
The structure should be populated only by active and engaged participants (e.g. “your tribe”). During “happy path” lower floors, especially the ground floor, can be used for commercial purposes. Only businesses with owners and personnel who are tribe members should be allowed to operate within the structure and firm commitment by dollar buy-in required. Tribe members should be alert to delivery and contractor personnel.
A well inside the building is easy, but there should be at least two. There are quite a few semiconductor manufacturing facilities with deep (500 ft or greater) wells inside their buildings to provide access to a very reliable electrical ground path by dropping >400 ft of heavy gauge braided copper cable into the well. If the “building plans” call for performing electronics manufacturing or repair, justifying the wells is easy.
Contractors From Outside Area of Operation
Contractors should come from outside your area of operation. The farther away, the better. There should be no duty overlap between contractors. For example, for the two internal wells, have different well drillers from different areas drilling their well in one section of the building (or what will be the future building) and at a different time than the other well is drilled. They cannot “compare notes”, because they won’t know any other well driller was involved. The same applies to electricians, plumbers, drywallers, et cetera.
Note: using 3/4 firecode-rated drywall is recommended but is rare enough that it will draw attention from suppliers and contractors, and simple tasks like painting, floor tiling, et cetera should be kept within the tribe. There will be “information overlap” with, and among, government inspectors, and inspectors do, and will, constantly have conversations with local contractors; inspectors will question why local contractors were not used, perhaps not to you but certainly to those local contractors. Try to keep information release to a minimum, but it will be extremely difficult. Having an “information management plan” from the outset is beneficial, and “legitimate” cover stories are part of that plan.
Ground water heat pumps are efficient but complicated and complex to support and repair, and replacement parts-dependent. Research them well before committing. Some use a more thermally conductive liquid than water in the piping. If a ground source unit is used, heat exchange methods should be duplicated and redundant. For example, have spare piping on hand in case of leaks, spare fittings, et cetera.
Whatever heat source is used, (lots) more insulation and reducing or eliminating air infiltration is key. The lower the demand is for heat, the easier it will be to meet that demand and the fewer resources that must be committed to it.
Buried Infrastructure Duplicated
Any buried infrastructure (communication lines, electrical lines, ground source heat pump piping, et cetera) should be duplicated and redundant. For example, put two complete sets of buried pipe in a trench for ground source heat pump use. Have one pipe circuit in use and the other capped for future use, in the event of failure of the primary piping system. This adds only the cost of the pipe. It’s the trench that’s expensive.
All trenches for buried infrastructure should be 50% deeper than everyone thinks they should be, and all buried copper or fiber should be laid in conduit with pull strings. Trench ends should have termination points inside underground vaults hidden below the surface. Digging three feet to get to a vault is easier than digging 10 feet to find the end of a cable somewhere in the dirt. All buried infrastructure should be very accurately mapped on a site plan, which must be very closely held under a very strict “need to know” basis. Remember, Luke Skywalker was able to blow up the Death Star because someone learned where the reactor vent was.
Draw-Down Capacity Well Pump
If wells are used for daily water, install enough draw-down capacity to allow the pump(s) longer run times. What kills submersible pumps is frequent on-off-on-off cycling, every time a toilet gets flushed or hands washed.
There’s a lot more, but this is too long already. The Urban Fortress is an interesting concept, but it strikes me as overly dependent on what may be (or become) fragile infrastructure, and it requires a sufficiently large commitment to exact, very substantial physical and psychological demands. In short, because so many eggs are in one basket, you won’t be able to walk away from that basket even if walking away is the right choice. I might suggest a less unitarian concept, one of multiple smaller nearby structures with overlapping responsibilities, capabilities, and authority, each capable of independent operation and mutual support but each also capable of being sacrificed if necessary without fatally compromising the whole enterprise. Humans can live, with some accommodations, after arms or legs are amputated; amputating the head, not so much.