A few corrections on the above posts. >It surely is asbestos. It is impossible to tell by sight whether a material is asbestos-containing. Only a lab test can do that. That said, one should always assume that it IS asbestos and treat it as such unless you do a lab test. >Begin by getting the best dust mask you can find at the hardware store. The mask you use should be rated 'HEPA' or have a 100 in the code (P-100 for example). Note, it is not the larger fibers but the tiniest ones that do damage to the lungs. Don't skimp on the mask. David R's description is pretty good but includes triple cleaning of all surfaces BEFORE the removal and no cleaning of the room AFTER the removal. I would clean after. >Call your city hall and ask where you can dispose of household hazardous waste properly. Follow their directions. >Which is the city dump, and you'll be charged 200% the normal rate. When the bags are taken to the dump, your name and address will be logged and now there is a paper trail connecting your name/address to asbestos disturbance. In the US, federal law exempts homeowners from many hazardous waste laws and regulations (and from asbestos abatement licensing requirements, if they do the work themselves). The concept of Household Haz Waste is actually an exemption from regulations for homeowners, not a bunch of special requirements on homeowners. Cities want to keep HHW OUT of the landfill if possible, so they ask people to voluntarily separate it and take it where it can be recycled/disposed safely. As for asbestos, a landfill is the one best place for it and there is no reason to divert it. It should be double or triple bagged AND labeled "Caution - Asbestos" and disposed with your regular household trash. You don't have to take it to the landfill yourself. That's federal rules; local ones may vary, so if you have questions, call whoever is responsible for your trash disposal and ask them what to do with X amount of asbestos removed from your house. You don't have to give them your address to ask questions, if it makes you feel better. I hope by now it's obvious that the 'disturbance', if done by the homeowner in a way that does not expose neighbors, the public or trash collectors, is completely legal and there should be no repercussions to anyone finding out that you did it. Just be safe. And if it's in good condition and hidden away from traffic/damage/etc. that would release fibers, it's fine to clear coat it and leave it alone. IMO that pic shows damaged/poor condition material and I would probably remove what I could easily access just to be rid of it. Very carefully. Or, you know, you can always test each separate material in your house at a lab for a few bucks, and if it's NOT, you can quit worrying about it! [If it looks the same on all the registers, it most likely is the same, so one sample is sufficient]

Did you actually cut through the tape? My experience is that tape similar to this readily absorbs water and is very easy to remove as a mushy pulp, without releasing fibers into the air. You have to pre-wet it with soapy water and keep it wet. It would then need to be double-bagged and disposed of legally. You could remove some in this way and get to a lab to verify if it is asbestos containing.

I have forgotten the exact pressure loss of the LD-10 silencer I was told when I asked Fantech for the value (at some flow rate). However, I do recall determining that it was too small to impact my overall system design. For silencer placement, consider the overall duct configuration from hood to roof. Where on that path is there a place where the silencer can be hung from the rafters and allow access without needing the butterfly stroke swimming in fiberglass. Pick the part of the reasonable location zone closest to the hood. The baffles need not fill the top of the reservoir under them so long as the reservoir depth is sufficient (and airflow rate sufficient) to keep the plumes entrained into the baffle gaps. Commercial hoods have baffle areas a lot smaller than their entry apertures, but have large reservoir volumes under them. Assume an effective capture area of 24 x 48 or 8 sq. ft. I would aim for 8 x 90 = 720 CFM actual, or a blower rated around 1100 CFM (at zero static air pressure). Whether passive is OK for MUA depends on whether there are any combustion appliances taking air from a space connected to the kitchen. In that case the pressure loss in your heated and filtered passive MUA has to be less than the back-draft pressure of the appliance. Second, the pressure loss has to be in your budget for your blower via its fan curve to still achieve around 720 CFM including baffle and duct pressure losses at 720 CFM. In other words, my giant WAG for scaling the blower rating to 1.5X the calculated air flow need depends on typical conditions and not restrictive MUA. You really don't want to feel air flow through your light switch plate edges when running the hood; it will pull dust and stuff into the house.

@sktn77a This is a very interesting idea. It seems like the main purpose of spray sealants is to seal the ducts from leakage, but as a bonus, the sealants may also help to encapsulate the asbestos inside the ducts. Sounds like the most effective solution outside of ripping out the old ductwork. Thank you for mentioning. @mike_home I'm not 100% sure whether the inside of my ducts are lined with asbestos, but I had an HVAC guy go into my attic years ago to take a look. He showed me photos of ducts that looked like long cardboard tubes and told me that's asbestos. I asked him the same question about whether it's maybe just the outside, but he seemed pretty sure that it was asbestos through and through (outside and inside). Would be great if asbestos was always just on the outside, but I did find this webpage that suggests sometimes it's not: https://buyersask.com/furnaces-acs-fireplaces/ducts/asbestos-ducting