Where can we discuss fire engineering?
I have some questions on smoke generation and fire growth etc. (BS 7974 related)
Address a problem when it shows up, not when it blows up.
Guys, thanks for the response.
It is assumed that the room will be unoccupied while the generator is running - the noise is so high that even with hearing protection it cannot be used.
The units are standby, diesel generators, 1250 kW, 1600 kW and 2750 kW - so pretty massive.
The airflow...
I am doing a project in the GCC - so ambient temperatures are seen as 55°C as per specification document.
So I get the heat rejection from the manufacturer - Q = X kW.
and I want to do a Q= m·c·dT calculation, but I don't know what an acceptable final temperature is for these high ambient...
In general, all HVAC equipment (that isn't smoke control) should be switched off in the fire zone where the fire is (for small buildings, that is usually the entire building). This is due to it being able to a) spread smoke, b) fan the fire (not nearly as important, since smoke kills people long...
The cooling required is TR (or kW) not CFM. CFM is airflow and if you reduce the airflow for the same Q you increase the dT.
Just bear in mind that the rated power is not necessarily what you can achieve with it. Quite often the rated power is calculated at 26C indoor not 21 C.
Kestell...
You want to control the pressure in the room, so you should measure the inside pressure vs the outside pressure - that is the "force" that the material of the room will experience.
Placing sensors in the rooms aren't always practical, then you measure in supply duct vs outside pressure - but...
Fans and pumps follow the same rules.
The question of how much you "lose" by adding fans/pumps in parallel is a direct result of fan/pump curves being superimposed over one another - the flow gets added onto the X axis, but the pressure not on the y-axis.
If you are operating near the top of...
Ashrae 62.1 section 6.5 says that you can use recirculated air, transfer air or outdoor air.
Having said that - it mentions a prescriptive path and a performance path - so if you read up on that section you should be good to go. I'd recommend also using CO2 sensors - even though CO is the more...
I think from an energy perspective, having a pre-cooling coil for the fresh air doesn't improve the efficiency significantly if at all.
Air to Air Heat recovery (desiccant wheel, run around coil or flat plate heat exchanger) will increase the efficiency of the system and on these systems you...
Please bear in mind that an AC is not always in Heating mode or in Cooling mode.
Usually, ambient air will help you one way (if you are in cooling mode, rejecting heat to the atmosphere en route will help you), but in heating mode, the flow is in the other direction, and now rejecting heat is a...
If I have a heat pump with backup elements, what would be the best (easiest/most reliable) way to control it, so that automatic changeover happens if the heat pump fails?
I thought of just doing it with different setpoints, but the elements will probably then work more than is energy efficient...
I have spent the last couple of weeks on this problem and it seems that the effect is the classical draw-off effect.
Where a shower is running and a WC/basin on the same line draws off water, the shower gets less water and the balance goes off.
What confused me at first was that the pipes seem...
Ok, after the weekend, the pumps were off, and the system is no better. I think the pipe sizes to the basins and the WC's are too large and aids the problem. Also the basins and the WC's are upstream from the showers.
Another theory that kind of ties in with the tanks acting like bladders, is...
Like I said previously, I inherited the project.
a quick order of magnitude calculation, using my regular spreadsheet shows that 300 l/min would probably have sufficed.
But in any event. We will be testing the system on municipal only first, then on pump only and if it works well on both, we...
