Car Park Ventilation

[PS]

Hello Professionals,

I was reading an article about car park ventilation. It was mentioned there are three methods to ventilate car parks.
(i) Open Sided Ventilation,
(ii) Natural Ventilation, and
(iii) Mechanical Ventilation.

I can understand that mechanical ventilation differs from the other two. But, what is the difference between Open Sided Ventilation and Natural Ventilation? Both Open sided and natural ventilation needs a prescribed amount of opening. How do they differ?

Attached is a file that summarizes Car Park Ventilation requirements according to British Standards. I am NOT able to follow the guidelines for NATURALLY VENTILATED TYPE car park. It is mentioned that GENERAL VENTILATION, here, requires more ACPHs than the FIRE EMERGENCY. Would anyone please share your thoughts on this? Sharing of any relevant sources on this topic his highly appreciated.

Thanks in advance for the efforts!

Attachment:

http://files.engineering.com/getfil...0a-498427d1064f&file=Car_Park_Ventilation.jpg

 

[dbill74]

What article were you reading?

 

[MFJewell]

I'm just guessing on the natural ventilation, but maybe they design the garage to draw in air at the bottom at entry points and discharge it through openings at the top level of the garage (kind of like a natural draft cooling tower).

 

[lukaiENG]

Open sided may be referring to free make-up with mechanical exhaust.
This would imply mechanical ventilation is mechanical exhaust AND mechanical supply.

 

[dbill74]

In the International Mechanical Code, the difference between natural and mechanical ventilation is the use of fans.
Natural ventilation is defined as "the movement of air into and out of a space through intentionally provided opening, such as windows and doors, or through nonpowered ventilators."
Mechanical ventilation does the same except for using mechanical devices (fans) to force the air into and out of spaces.

As the OP worded, I am confused about the "Open sided" ventilation. As I see it, this is more a subcategory of mechanical and natural ventilation designs. In a parking garage, both natural and mechanical ventilation design can utilize an open sided structure.

This is why I want to know what article the OP was reading, perhaps I can glean more information about what is being stated and asked.

 

[PS]

Thanks ALL, for your kind replies. Given below is the link, I was referring to.

http://www.proidea.hu/colt-hungaria...am_cyclone_garazsszellozteto_rendszer__en.pdf

The image that was attached earlier was from a presentation in slideshare stating it is the summary of BS 7346-7: 2006. The link for the presentation is below:

https://www.slideshare.net/Colt_UK/cpd-car-park-ventilation

Slide 7 shows the summary of the three types of ventilation: Open-sided, Natural, and Mechanical.

Please do let me know for anyother clarification.

Thanks, again!

 

[dbill74]

I can understand that mechanical ventilation differs from the other two. But, what is the difference between Open Sided Ventilation and Natural Ventilation? Both Open sided and natural ventilation needs a prescribed amount of opening. How do they differ?

Per the article, the difference is the presence of exhaust fans to help remove exhaust fumes; open sided has no fans while naturally vented design does.

IMHO having fans in the "Natural" vented design would make it a mechanically vented system. An issue of definitions it would seem.

 

[PS]

Yes, @dbill74. Thanks for the reply.

That is the thing which confused me. I am observing it to be "NATURAL applies only during Fire/Smoke situation, whereas during car-fume extract it acts as a mechanical ventilation system and Open-sided ventilation is natural ventilation in both the situations, fume extract and smoke extract." I just wanted to know whether I am observing it wisely or not.

And per the code's requirement for Natural Ventilation, general car extract requires more ACH than during emergency (smoke clearance). How do you view this? From a layman's point of view one need more ACH during emergency than during normal ventilation. But, the code tells the opposite.

Thanks, again!