UNDER THE CONCRETE FLOOR of a storage closet that houses our sanctuary building’s electric meters, under the shed roof between the building and the play yard, is an opening to a vertical shaft.
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| Raised platform on floor of storage closet (marked by dotted red lines) |
Below the jump, this post describes the shaft’s configuration, how it connects to the basement, its purpose, and its history—according to inferences drawn from my exploration of it this week.…
WHEN THE TECHNICIANS from the Gas Company came to restore service after the fumigation was completed, they red-tagged our school building’s furnace as having a safety issue, due to the closet that houses it. Namely, they perceived two ways that post-combustion exhaust gases from the furnace just might get sucked by the blower into the air that is circulated through the building, rather than being vented up above the roof.
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| A gas company technician explains the problems. |
Honestly, the hazard did seem pretty unlikely to me, given the configuration of equipment. Yet Fleming and I took the recommendations seriously, especially for the sake of our preschool. The resolution seemed simple if we could find the right person to handle it. So we made some inquiries—and within 6 working days the problems were fixed, for about $150.
Below the jump, this post documents the two suspected problems, as well as their resolution. I created this post because given normal wear-and-tear, these apparent hazards will eventually appear again—and will need attention in the future.
THIS YEAR, with the incidence of Covid-19 infections at a moderate level and a predicted high temp of 78° for Rosh Hashanah, we implemented a particular plan to provide reasonably healthful air for attendees at our High Holy Day services.
JUST IN TIME for the High Holy Day crowds, a pair of air purifiers was installed yesterday in our historic sanctuary’s HVAC system—one for each blower. These devices use needlepoint bipolar ionization (NBPI) technology, as described HERE—from when we were preparing to install one in our school building.
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| One of the new ion generators, mounted inside the forced-air unit (FAU) |
These ion generators are designed for a system that is up to 2.4 times as large as ours. That’s good, because our retrofitted system is only about half the size needed when the sanctuary is full of people. In other words, our air purifiers are properly sized for the space.
For links to evidence that the ions produced by this device are indeed effective at neutralizing airborne pathogens directly, see HERE.
ALTHOUGH I HAD provisionally concluded that duct smoke detectors were not required in our sanctuary, as described HERE, I nonetheless looked for an opportunity to get an authoritative opinion. That opportunity presented itself exactly one week ago, when Tom Nasrollahi, a mechanical (HVAC) engineer, made a site visit as a consultant on our main-floor restroom renovation project.
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| One of the new duct smoke detectors |
Unhesitatingly, Tom replied that these devices were indeed required in our sanctuary, according to code.
He explained that even though each of the sanctuary’s two systems has its own thermostat and each one by itself has a small enough blower to be exempt, they must together be treated as one overall system because they both participate in conditioning the same space. The system’s cubic feet per minute (CFM) for the total space is what counts.
Happily, a pair of detectors was installed yesterday. They were placed just upstream of the air filter before the blower intake (see photo).
Thus we have made a capital improvement (betterment) that addresses a life-safety risk, which is of course the highest priority use for our precious funds.
(How did it come about that the installer of our replacement heating system in 2017 did not include these devices at that time? Maybe I don’t want to know.…)
ALTHOUGH SELDOM NOTICED, a plenum (shaft) runs from floor to ceiling through the lobby-level “Ladies Lounge.” (It continues through the mezzanine, too.) It’s behind the wall that is straight across from the door to the lounge from the lobby. What is it doing there?
Below the jump, this post discloses what’s inside that plenum—and why.
IN FEBRUARY 2023, I described the sanctuary’s HVAC system in this post. Just recently, I have revised three aspects of my earlier understanding. The newer picture looks like this:
Below the jump, this post describes and documents the salient results of what I learned from my recent explorations.…
OUR PROSPECTIVE CONSULTANT, a mechanical engineer, has observed that our restrooms have exhaust fans yet no clear way to replace the exhausted air. He believes that in order to approve our permit for expansion restrooms, the City might well require a dedicated source for intake air. (HVAC people call it make-up air, presumably because it “makes up” for the lost air that the exhaust fan is removing from the room.)
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| A typical restroom exhaust fan |
This raises the question: What is the best way to supply make-up air to our restrooms?
This question will eventually apply also to the basement restrooms, since they are likewise slated for eventual expansion. So let’s think about a comprehensive solution that will work for them, as well.
Below the jump, I offer a couple of cautions about one option that the architect has mentioned as being fairly normal. Then I outline a custom alternative that takes advantage of our building’s unique configuration [revised 9/10].…
A DUCT SMOKE DETECTOR is an HVAC-system device that can prevent flames and smoke from being spread or fanned by the system. In the event of smoke, the detector sends a signal to shut down the fan. Its presence is required by code in most circumstances. Normally the determination is made by city building department officials when a permit is applied for.
The HVAC contractor Jessy Perets told me that our sanctuary’s HVAC system lacks duct smoke detectors. He also pointed out that our twin HVAC units were installed in a visibly low-budget manner, apparently without a building permit. Which has led me to wonder whether or not a pair of duct smoke detectors were technically required in our case.
For a fire safety measure, the fact of requirement (if it indeed exists) would argue for installation after the fact (which would cost $1,275 as quoted by one contractor). Conversely, if our case is an allowable exception, that would argue for leaving things as they are. At its June meeting, the board adopted that approach and asked the B&G Committee to find out whether duct smoke detectors are required by code in our sanctuary.
I have a provisional answer, which I lay out below the jump.…
AN EXPERIENCED H.V.A.C. CONTRACTOR submitted today a proposal for a two-stage HVAC system for the Social Hall. The installed cost of a ventilation system would be $28,000. Later, we could add heating and A/C for another $21,600, plus the cost of electrical work. Subtotal: roughly $50K.
I asked for this bid because the Ad-Hoc Committee on Capital Priorities recently named such ventilation one of its top five items:
“The Social Hall should once again become an integral part of Mishkon’s life. [It] needs new ventilation and heating.”
Below the jump, I describe the elements of the vendor’s proposal and discuss them, including related options.…
I AM PLEASED to report that the air purification device described HERE was installed today.
Below the jump, I give links to evidence that the ions produced by this device are indeed effective at neutralizing airborne pathogens directly, quite apart from whether the resulting agglomeration is ever trapped by the system’s air filter.…
WE HAVE SELECTED the most appropriate air purification device for our school/office building. It is a NuShield-R, which is a compact unit—smaller than a cigar box. It uses needlepoint bipolar ionization (NBPI) technology.
It appears that we can count on the impending air scrubber to significantly reduce the airborne transmission of disease inside our school building — as long as the hallway doors are kept ajar, so that the air can keep circulating throughout the building.
Below the jump, this post explains this unit’s benefits and features.
ACCORDING TO OUR JANUARY 2019 Property Condition Assessment (PCA), our school building’s HVAC units (= furnace, A/C fan coil, and rooftop A/C condenser) were likely to need replacement by 2024. So for more than a year, I have been bracing for an equipment failure any day now.
Below the jump, I recount the ironic tale of how I learned this past week that we can expect many more years of life from our HVAC equipment in that school building.…
OUR RABBI MAY WELL be the biggest beneficiary of the security windows that were installed in December. I’m not talking about protection from potential attacks. I mean on a more tangible, everyday basis!
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Below the jump, this post explains why I say so.…
IN THE WINTER, it’s a challenge to protect our worshipers from airborne illness while also keeping them warm enough, and while minimizing water damage to our facilities from rainfall. Fortunately, given the relatively temperate climate in Venice, we face this challenge only a few months of the year. Yet during those months, the situation requires active management.
The HVAC control interface via the internet
(As usual, click/tap on an image to enlarge it.)
Each week during cold weather, the trade-offs need to be weighed. Factors include predictions for the outdoor temperature, the wind velocity and direction, the amount of rainfall — and how prevalent and how severe the covid-19, flu, and RSV infections are locally.
Below the jump, this post discusses the challenges and trade-offs. It suggests some management guidelines, based on my experience last winter.
THERE’S A LOT of room for improvement in the HVAC system of our school/office building. Thermal-comfort levels are good but not great. Our hospital-grade filter is reducing the risk of airborne disease, but it is taxing the air-supply blower. Running more than 45 hours per week, this HVAC system is much more heavily used than the one in the sanctuary. That’s why in July, when a preschool parent expressed interest in funding a system upgrade, it became my personal highest-priority new project for Mishkon. (This one is moving slowly, however, because I’m still heavily involved in old projects.)
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| A return-air register for mounting in a door (As usual, click/tap on an image to enlarge it.) |
Below the jump, I discuss the prospects for improvement. This work would be done in late December, during the preschool break.…
WHAT’S THE CONFIGURATION of the heating/cooling system in our sanctuary?
This post gives you a basic picture, through verbal description and photos.…
PICTURE A HALLWAY that’s lined with doorways. You might think that in a proper hallway, all those doors should be closed. A nice and neat look, yes?
Yet that is not how our school building was designed to function!
This post discusses our building’s characteristics, and how best to work with them.…
WE HAVE LEARNED this winter that on cold days, the heating system in the sanctuary has not been able to heat the room adequately while the doors and windows are open (as needed to reduce the risk of airborne infection). The relatively cold room has been uncomfortable for some, and a frustration for those who feel responsible for the situation.
One factor to consider is the heating system’s air filters, which probably affect its ability to heat the room. This brief post discusses the impact of those filters, and related considerations.
