How much is enough Make-Up Air
lurker3197
5 years ago
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5 years agolurker3197
5 years agoRelated Discussions
How much urine is enough - or too much?
Comments (7)Experiment. Pick a couple volunteer plants and keep adding more and more until they can't take it any more. Plants can typically take and like much more than you'd expect. You probably cannot add too much if it is diluted. Took me 2 cups of undiluted poured right at the stem of a 1' tall tomato plant to kill it. when I poured the same amount 1 foot away the plant enjoyed it....See MoreBloom Boosters - How Much P is Enough?
Comments (8)So sorry about the text in the OP. ;-( It was indeed a copy/paste job from one of my older posts, with a few changes. I hope you find (found?) it worth trying to figure out. Anything we add to our soils that isn't needed and finds it's way into the soil solution has the potential to limit growth/vitality. Many growers cling to the idea that a little more of this or that nutrient is better - for instance that since a little extra Fe or Mg will green up a plant, it must be good for it - true only if the plant is deficient in one or the other of those nutrients. Greener does not mean healthier when it comes at the expense of an excess of one or more nutrients. Since aquarium water contains a number of nutrients, is it necessarily a good idea to use it? So what's actually IN aquarium water - anyone know? Not with any certainty, so it's a very good bet that A) if you use aquarium water as your sole nutrition source, there are bound to be deficiencies, and B) if you combine using aquarium water with a sound nutrition program - 'because a little more of this and that is better' - you end up duplicating nutrients you don't need, which we know from Liebig's Law of the Minimum has the same potential to limit as a deficiency. If you rely on a sound nutrition program with no extra little treats, you're much more apt to end up with a lean mean growing machine. Whenever I consider anything as a supplement that my plant might need, I ask two questions. A) What will it supply that I know my plant needs? and B) What impact will it have on the soil's structure? In the case of worm castings and seaweed (other than emulsion), they supply nothing a plant needs that can't already be found in a fertilizer like Foliage-Pro, and they have only the potential to reduce aeration and increase water retention in container soils; though to an insignificant degree in the case of fish emulsion. So on two counts I would avoid them in my soils. Actually, there is a third consideration. I also tend to avoid the addition of soil amendments added for their nutritive value if I think they will promote significant growth of soil biota. I love it in the garden, but we can grow just fine in containers without courting the micro-herd. If we are going to use practices that support large populations of soil biota that break down soils quickly, why bother building all that wonderful aeration and drainage into our soils, only to have them stolen as our soils collapse in a feeding frenzy of micro-organisms? Growing in containers is well removed from gardening, and much closer to hydroponics. On a scale of 1-10, with growing in the garden being a 1 and hydroponics a 10, container culture is probably a 7 or 8, which is why a good part of what works so well in gardens (compost and organic amendments, worm castings, bone/blood/feather meals, feed the soil instead of the plant, .....) doesn't work well in containers. There's just no substitute for a healthy root system and a sound nutritional supplementation program that the grower assumes responsibility for and control over. Al...See MoreBox in my NG water heater and plumb it for combustion and make up air?
Comments (21)"And that would be super-awesome if #5 applied. Read again." I just did. And I read it a few times before I posted. The section is "Fresh Air Openings for Confined Spaces." The subsection (B) is "All Air from Outdoors." #5 says: "5. Alternatively a single permanent opening may be used when communicating directly with the outdoors, or with spaces that freely communicate with the outdoors. The opening shall have a minimum free area of 1 square inch per 3,000 Btu/ hr of total input rating of all equipment in enclosure (see Figure 20)." Maybe you are focused on "all equipment in enclosure?" The only thing in the enclosure would be the WH. It would be helpful if you gave me a hint as to why #5 doesnt apply. Anyway, I think what I will do is ... nothing. Before I tear out a perfectly good WH that I haven't even made a mortgage payment on yet, I should probably wait and see whether I actually have a problem. I have CO detectors throughout the house so presumably I will know if there is a back draft situation. Thanks a lot for all the replies. They were very helpful in helping me think this through....See MoreVent hood question - make-up air turbulence, acceptable neg pressure?
Comments (13)This is an issue that requires some measurements and some analysis. To even know where you are you need to measure the pressure in the house relative to outside the house as a function of different settings of vent air flow and MUA air flow. Either hire someone to make the measurements or buy (cost is fairly modest, as I recall) a differential air pressure device. In test kitchens, the means of introducing MUA is via a perforated wall some distance from the test stove/vent air handling equipment (hood). What is desirable is that the MUA, when it gets to the air volume between the cooktop and the hood entry aperture, be relatively non-turbulent. Introducing MUA at one's feet next to the stove may or may not achieve this. Often the toe kick spaces there are too small, and may, depending on configuration, aim at some other structure (wall, island, whatever) that will force the air flow up. Now there is turbulent air all around the cook and the hood. I think the MUA exit area(s) should not be too much smaller than the hood entrance area unless the MUA injection point is fairly far from the hood. In a (completely burger odor free) burger joint in Concord NH there is a CaptiveAire system in which the MUA is expelled downward from the ceiling in front of the hood. (This aperture is actually part of the hood assembly.) I would estimate that the MUA aperture is roughly half that of the typical very large commercial hood aperture, although I cannot see all of the hood aperture from the customer seating area to be very exact about this. In my residential configuration, a 3 x 3 foot ceiling diffuser is used about 20 ft down a hall from my 10 sq. ft. aperture hood. This hall delivery should slow down the air velocity to about 37 ft/min, which is a slight breeze -- less than a half mph. I haven't pressurized the MUA yet, but I have seen the effect of an interior split cycle air conditioner head spilling air toward the hood, there is significant plume displacement. Is your MUA source via a basement, or via the roof? It might be better if you dumped the MUA at the ceiling directed away from the hood such that the air takes a longer path to the hood aperture. Or dump it into diffusers at various locations in ceilings connected to the kitchen. (This might be a casus belli if not heated.) Or use a lot more toe kick area. Besides measurement, I would check that with windows open, MUA off, and hood on, that you can cook something and see it fully captured and contained by the hood system. Then as you close up windows, and do whatever you are doing (manually?) to set MUA flow, does this start interrupting the capture efficiency? And yes, if you don't have a closed loop controller then both hood and MUA should have continuously variable controls. By analysis I meant making a gross estimation from the hood system fan curve and the properties of your vent system of what flow rate you may be achieving. (There are contractors who can measure this by temporarily replacing a door with a measurement device.) Ditto for the MUA system. What is its fan curve vs. ducting, filtering, diffuser pressure loss, and heating scheme, if present? If your actual replacement air is 200 CFM, then ideally you want the MUA to be 200 CFM less than the hood can pull when the house pressure relative to outside is zero. One expects that if the house pressure is positive, more air will flow out the hood system. But in your case I suspect, as did opaone above, that there is really a lot of turbulence around the hood and this turbulence is interfering with the cooking plumes attempting to rise to the capture area (the hood entry aperture). kas...See MorePinebaron
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