Live Load Reduction for a Room Growing Cannabis 5

[Datonedavid]

Hi, Everyone.
I got a client who has a factory who wants to remodel the second floor to grow cannabis.
In terms of Live load I think the description best meets a greenhouse which would would rate it at 125 PSF.
When I asked the client how much their plant weighs(soil,plant,and water combined), the amount of plants in the room, and the area of the room it comes out to 4 PSF.
I spoke with building official and he said that he would entertain a "rational" live load reduction proposal under Section 1607.12.2.1 of the IBC.
But I'm unsure what qualifies as rational approach pertains.
Would love to hear your guys thoughts on what the correct live load should be and reasoning.
Thank you for your time.

 

[bones206]

Now that I’m aware of the greenhouse 125 psf LL in the code, I’d probably stick with that going forward for this type of facility just to avoid any questions. The edge case of stacked pallets of growing medium that someone mentioned is compelling.

I think I probably(?) met the spirit of the code for the rationally analyzed load reduction, by checking all the operating loads and providing a robust capacity. This is essentially what was done in that Oregon case I linked to, except that was documented and approved. I think their analysis showed less than 10 psf actual load.

 

[JAE]

How does posting the live load accomplish anything? Which employee is qualified to determine if they are exceeding this?

Well it does accomplish risk reduction for the EOR if later they can prove the load was beyond that amount.

It's in the code to post live loads when appropriate.

I have had owners call me many times about posted live load signs and their concerns that current loading was exceeding it. So some owners aren't so dumb as to not sense a problem. Agreed: some are.

Insurance companies require posted live loads on mezzanines and other areas they feel might be at risk of overloading.

So it is a part of our engineering heritage, codes, and practices.

 

[Datonedavid]

I want to thank everyone here for their input. Obviously I would never rate it for 4 PSF, I just brought that up cause I thought wow these plants are light maybe we can go less than the Live load of a green house.
I was thinking of combining that load with 40 PSF for foot traffic from employees and some factor or safety and get something like ~90 PSF, but you all brought up good points I'm not considering long-term.
Also my mistake Greenhouses are rated for 150 PSF not 125 PSF. I found it under Table C4.3-1 of the ASCE 7-16 commentary version.
Once again, thank you for taking the time to comment, it was insightful to see what you all thought.

 

[JAE]

I'm not sure if I missed it but did you ever find out (or post here) what the actual, current capacity of the floor is?

 

[Datonedavid]

[/I'm not sure if I missed it but did you ever find out (or post here) what the actual, current capacity of the floor is?
]
Correct me if I'm wrong but I think it's rated for a Dead Load of 20 PSF and Live Load 40 PSF.
It is currently classified as a mech room. But nothing too heavy. Just HVAC and ventilation stuff.

 

[Heaviside1925]

OP,
I don't know if the client has provided you with a layout, but I have been involved with hydroponic systems for cannabis. I ask this because there could be equipment, or vessels/tanks not normally considered in a traditional greenhouse. Additionally, if they are doing any processing, such as terpene extraction, there could be additional equipment for this as well. Just saying all of this because there could be some highly concentrated loads as well depending on the equipment and layout.

 

[Datonedavid]

I was given Layout plans. I'm seeing things like fan coils, Glycol Feeders, Storage Tanks, Expansions tanks, and Boiler. I'm not too familiar with these equipment relevancy so I'm not sure if any of these are a lot heavier then they sound.

 

[EngDM]

I'm seeing things like fan coils, Glycol Feeders, Storage Tanks, Expansions tanks, and Boiler.

I'd be asking for cut sheets/weights for any and all equipment, given that the equipment is probably pretty specific to canabis production and may be a-typical to what you are used to for weights.

 

[Heaviside1925]

OP,
If these have already been specified or purchased by the client, then they should be able to provide the weights. When I hear tanks, I think of dead loads, when I hear pumps, I think of dynamic loads. They may all be well within the load capacities you are using but if the information is available then it might be worth a check.

 

[Heaviside1925]

I'll add an additional note that there may be occupancy classification and usage considerations may be different than what is being assumed for just "growing some plants". It sounds like more of a process driven type of set up. Not sure if it falls into a high hazard group but based on the equipment you are describing, there could be flammables and combustibles, storage and usage involved as well.

Side note. I had a friend involved in the cannabis industry in the PNW. He put me in touch with a prospective client who needed an HVAC system designed for their cannabis growing operation. With my friend as the intermediary, I started asking questions.
Me - Why do they need a conditioned space? Offices? I figured with just growing plants outdoor ventilation would be adequate.
Response - I'll ask and get back to you / Well because the fire marshal shut them down until they can produce an engineered HVAC system.
Me - Oh, so they skipped some building codes and permitting. Got it. Any idea what design conditions they need?
Response - I'll ask and get back to you / They need a system to handle the flow rates from their ventilation hoods.
Me- What ventilation hoods? What are they ventilating?
Response - I'll ask and get back to you / Ether and methyl alcohol.
I am paraphrasing and wish I could find the exact text exchange (much more colorful) but as you could guess, they had a whole host of other issues and after finding out what it was going to cost to make all the required improvements, I think they had to roll up shop.

 

[bones206]

roll up shop

I see what you did there ;-)

 

[Tomfh]

Layout plans. I'm seeing things like fan coils, Glycol Feeders, Storage Tanks, Expansions tanks, and Boiler. I'm not too familiar with these equipment relevancy so I'm not sure if any of these are a lot heavier then they sound.

This is good. By knowing the specific equipment (including its weight) and the locations, you can make an accurate assessment.