CO Control - Car Park Ventilation (BMS)

[@cyrilcruz6428]

Thank you. I learned a lot.

[@frozenlkea6188]

Great video Bryce. Just wanted to note that Mechanical Engineers would typically size the supply air make up fan to be at 80% of the exhaust air flow rate anyway. So in theory if the BMCS signal is 10V (100%) it would be the Max design airflow of both fans, and if they sized correctly, space would be negatively pressured. A 9V signal might be too overcompensating perhaps? Not sure, keen to hear some thoughts. Anwyays great informative video.

[@bryceanderson17]

I agree Leo, if mechanical engineers size the supply air fans smaller then the BMS can send the same signal to both as you have described. Thanks for clearing that up. Cheers.

[@mattgraham364]

Great simple explanation thanks Bryce

[@bryceanderson17]

Thanks :-)

[@guestuser14341]

It is a good information. Keep uploading...

[@bryceanderson17]

Thank you :-)

[@amerhnajjar]

Hi Bryce .. great video as usual. Quick question, in the staffed car park, how to start running the fans at CO 5ppm while OA already has CO 9ppm ? Unless these values are relative to OA ? It makes more sense in non-staffed CP as fans start running beyond CO 9ppm up to CO 60ppm, which CO 51ppm total inside the car park. Can you touch base on this one please ?

[@bryceanderson17]

Hi Amer, In staffed car park, the fans start at min speed when the max CO is above 7ppm, and switch off below 5ppm. In non staffed car park, the fans start at min speed when the max CO is above 15ppm, and switch off below 9ppm. AS1668.2 does not describe any CO values relative to outside air CO. Hope that helps, otherwise get my number and call me, cheers.

[@ahmedrefaieemara1512]

Interesting Bryce, but regarding the point of makeup airspeed wrt exhaust fan speed, I think that considering makeup fan capacity equal to exhaust fan capacity but running at lower speed is not optimum in terms of CAPEX, it is more valuable to consider makeup fan running at full speed but with a capacity of let's say 85 % of exhaust fan capacity. or What do you think

[@bryceanderson17]

Hi Ahmed. You are correct 😊

[@arsalanzahid6434]

Hi Bryce, thanks. Great explanation. Do you also cover all these pieces in your training course "Advanced Control Strategies"?

[@bryceanderson17]

Hi Arsal, yes there is some overlap in the online course. However, most of the online course is not on KZbin. And you get the control strategies written out in the training manual. There is significant additional course material on AHU systems and water systems not discussed on the KZbin channel. Thanks for the support.

[@arsalanzahid6434]

@@bryceanderson17 Thanks Bryce, I will be registering for two for the courses this year :)

[@abdulhalimkolko]

Should the reading from multi sensors in a single level / zone be averaged?

[@bryceanderson17]

The Australian Standard AS1668.2 clause 4.11.2 says the following: ... ventilation rates shall be varied such that when the concentration of contaminants measured by ANY sensor within the enclosure... Therefore, we need to do a maximum select and NOT an average select of all the sensors. Code requirements may be different in your country? It makes sense, if one level of the car park is very busy, the entrance to the shopping centre, but the other 3 levels are empty, then average would provide a false reading for the busy floor. Thanks..