All,
So last year I posted a question re: how to resolve white rust on interior sheet metal duct wall. That thread has been closed, but here is the link:
https://www.eng-tips.com/threads/how-to-resolve-white-rust-issues-inside-ductwork.521755/#post-9014179
I recommended to the owner that the...
3DDave - Point taken... But this project has been under construction for over 10 years... 10 years of Construction Admin weekly meetings on a project literally 5000 miles away, that was to have had a 24-month schedule. I just cannot keep fighting every issue; especially one involving a request...
3DDave - Thanks for the reply.
In this case, as in many... neither I, nor the facility has the time to fight this borderline idiocratically (apparently not a word, but it should be...:-)) written code section.
So instead I'll finish the design in compliance with NFPA, and the facility will...
Pedarrin2 - Thanks for the response.
I understand the Code - I quoted it.
However... the way it is written is appalling.
"... cannot interconnect with other facility air-handling systems that serve locations containing combustible or flammable materials".
For pete's sake... An employee in a...
I am designing a couple small Med Gas Storage Rooms in a Hospital; (4) K cylinders each of N2 and CO2 (about 300 ft^3 each tank, 1200 ft^ 3 each room, 2400 ft^3 on this floor). These will be in separate rooms, although it is technically not required.
NFPA 99 2018 requires 1-hr walls, with...
Thanks all,
This is indeed a unique place. The population is about 50k, and they basically govern themselves with US aid.
Which also means they need to comply with US standards (ICC Codes, NFPA, ASHRAE) for all major infrastructure, like hospitals.
Unfortunately, there is a dearth of...
All,
Have an interesting HVAC project that is Morgue related.
I have done a few full Morgues, with the required viewing areas, autopsy tables and body reefers.
This is different.
A facility on a remote island I am temporarily working at wants to increase their deceased body storage holding...
Thanks gents for the knowledgeable comments. I have advised the Owners Rep I am dealing with that while there are a few ways to remediate this, all involving considerable time and expense, and the result will still not be equal to new pipe. You paid for new pipe; not refurbished pipe that may -...
LitleInch - seems our posts passed each other.
We are using VIC couplings; too hard to get reliable welders around here. VIC also provides some...flexibility... in piping systems during seismic events. This place is rated about the same as Los Angeles and San Fran for seismic concerns.
A grit blaster is a great idea - as long as it could be put on an extension that is appx 10 feet in length to reach the halfway point. Air compressor should be no problem.
I am more than a little concerned about the degradation of the cut groove that the gasket fits in. This is/was...
Did a search and could not get an apropos result.
I'm assisting a US based facility on an island, and a Contractor has had a half dozen nominal 20' sticks of S40 A53B 6" grooved piping sitting outside in his storage yard. For years. It is to be used in a chilled water distribution system (40F...
Finally found what looks like an authoritative source of white rust info - from the grain silo guys!
https://scafcograin.com/wp-content/uploads/2019/07/19-7-White-Rust.pdf
An interesting read. It makes a lot more sense than a couple Contracttor sites I found with advice to basically "leave it...
All,
First, my bad on the LAT conditions. This project has several AHU's, and the 55DB/55%RH were from memory. The unit in question has a 51DB/51WB 100%RH LAT, while the adjacent OR AHU has a 58DB/50WB/55% LAT. 38F CHW temp and Heat Pipes in the OR AHU - pretty cool tech. There is also...
Good story! Amazing what you have to do sometimes to convince folks you know your job...
I talked with another guy at our firm who retired a couple years ago; he had not seen anything like this either. He had a better idea for a liner though - literally cut to fit and screw on another coat of...
Thanks Heaviside1925 -
These ducts indeed just see conditioned air - hopefully 55F@ < 55% RH. My client is the facility, which in this part of the world, is also the AHJ. Yes, it's weird.
The vinegar wash/scrub would indeed be a mess. I also do not know of any spray galvanizing that is...
Our firm used to do multi-disciplinary work for the VA at several sites, as well as wrote the first couple versions of the HVAC, Plumbing, and Electrical Design Manuals. The VA has 165-ish major hospitals, and almost 3x the number of Clinics and smaller facilities. So when they have a problem...
I am helping a client commission some medium sized (34,000 CFM) chilled water AHU's that were installed several years ago, but never started. This is in a hospital, on an island with lots of rain and high humidity.
In cutting into a large (10 ft x 3ft) vertical SA plenum in order to get to some...
Thanks for the quick responses gents.
Heaviside19125 - guilty as charged. I was off in my pump data - it is 70' head, appx 30 psi. We are also at 40F design temp. My min shutoff head is 115 psi. Using piping manufacturer pressure tables (primarily because most HVAC firms don't deal with ASME...
