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Hi all, I'm sorry for posting, but unfortunately the search isn't working. Could someone please explain the difference between a floating ball valve and a trunnion mounted ball valve? And what is double block and bleed on a trunnion mounted ball valve? Thanks in advance.

Hi all, I'd appreciate it if someone could set me straight. I am working on designing an exhaust fan for a small building. I have calculated the heat gain for the room and know that the outdoor design temperature is something like 28*C while the desired inside temp is about 20*C. Using the...

Goodmorning All, I am trying to calculate a rough estimate of heating requirements so I can size some electric heaters. I’d appreciate it if you could tell me if I am heading in the right direction. 1. I have calculated how much heat will be lost from the building assuming that the walls...

I am trying to size a heater for a building in a cold environment. I am not sure what outdoor temp I should use from ASHRAEs "Heating and Wind Design Conditions". Should I use "Heating DB 99.6%" or use "Coldest Month MDB 1%" Thanks for your help

I am working on a project where I have to put a new HVAC system in a building full of pipe transporting hot bitumen and steam. The building is H5.2m x L15m x W7.2m and is at a temp of 40 deg C. How should I approach this problem? I have been told that there are not many people in this...

Using basic heat transfer rules I have determined how much heat will enter a room on the "design day". I have also added the amount of heat rejected from equipment in the room to determine the cooling load on the air handling unit responsible for cooling the room to a predetermined...

I was recently told from some field operators that they are having trouble opening and closing ball valves. As a matter of fact they are having such a hard time closing the valves that they are bending the handle. Are welders expected to remove the bonnet and the contents of the valve before...

When I read, for example, 8 air changes per hour I get the impression that I must replace the room 8 times in one hour with FRESH AIR. Is it FRESH AIR? Thanks

I was told a while back from this very useful forum that you shouldn't take the tag value of a piece of equipments heat dissipation when calculating the total cooling capcatiy of an AHU. I was told to that the air handling unit would never have to handle the full 100% load, instead take 60% of...

Here is one that will put us all out of a job. Does anyone know of a company that designs self cooling buildings? If not, have you ever heard of such a thing? Thanks For your help, Dave

Are you aware of any testing that is completed to ensure zero/minimal air loss in duct work? Is this standard practise or a requirement? Thanks for your help. Thanks

I am working on the design of an HVAC system for a plant located in Africa. Total Heat Dissipation is based on Instrumentation(62kW) and lighting(11kW) totalling approx. 92kW. The Vendor is saying that this number is too high too cool. But the fact is is that these values are as such so the...

Can someone please supply me with industrial duct sizing chart from SMACNA. Thanks for saving me a hundred bucks. Dave [lightsaber]

To calculate the fan cfm for my air handling unit should I use: 1. CFM=Qlatent/1.1/(Toutside-Tinside) OR 2. CFM=(BuildingVolume)*(AirExchanges/hour)/60? If I do use the first equation, then for different loads (coolong and heating) the cfm works out to be different. Should I size the ducts...

Please confirm that this is incorrect. If you place a 1200 cfm fan in series with a 1200 cfm fan you get the combined 2400 cfm. Company X says that this is a choice that I have, but I disagree. Thanks Credible Sources.

I am a recent graduate in need of help from you, the experienced HVAC&R engineers/technologists. Here is the situation. There is a small building with an existing electric heating unit in it. Although it DOES supply the correct CFM it does not supply the correct amount of heat. (15kW versus...