Almost all projects start with the creation of a team with representatives from all various areas of responsibility including the developer, real estate broker, designers, project managers, field supervisors, owner representatives, possibly tenant representatives, and possibly key subcontractors.
Most team processes will include meetings, meeting minutes, detailed plan and specification reviews and approvals, and accuracy validation of many of the early-established project criteria. This process needs to document the preciseness of the project design with respect to the existing conditions, and appropriate application for meeting or exceeding the operating performance criteria of the tenant or owner.
With the often unfamiliarity between new team members and potential different interpretations of the same written information, good communication starts with good questions and detailed thoroughness of responses.
One of the most important new or existing building physical limiting criteria is the “clear height”. This information is frequently listed in real estate property listing brochures or flyers, project outline performance specifications, or detailed contract requirements. My experience is this information is most commonly defined as the distance from the floor slab to the lowest structural roof element, usually a bar joist or joist girder at the location of a roof drain.
If the definition is understood by the whole team and is accurate, it is helpful in planning for intended racking or stacked storage heights for the building occupant, but, keep in mind, it can be defined differently, not properly calculated for a project, or not provide enough information solely by itself for rack storage height design.
Below are “Good Questions” to avoid “Unwanted Surprises” on your next project with respect to “Clear Height”:
- Independently of the structural clear height, what height does the current proposed or existing fire sprinkler design density permit for your intended product commodity type, number of aisles, and depth of materials in racks?
- Does the roof slope from the low point at the roof drains to the high point permit racks resulting in different heights at different locations in the building?
- What other mechanical, electrical, fire sprinkler, cable tray, fire alarm, plumbing, or overhead cranes rail obstructions impact the ability to install racks in the space?
- Double check with existing buildings that the clear height calculated or published in the listing brochure is accurate for the lowest structural member and not the metal roof deck, or inadvertently taken at a location other than the lowest roof drain constraint.
- Once the building clear height is established and confirmed make sure the proposed height and product weight being transferred into the concrete floor through the lowest pallet for free-stacking product (or rack leg base plate for rack stacked product) can be adequately supported by the concrete floor slab weight capacity. Most leases pass along concrete floor condition responsibilities to the tenant and overloading a floor and replacing or repairing the concrete following the lease term expiration is an “Unwanted Surprise” most companies do not want.
- Make sure critical structural member depths are not deviated from during shop drawing approval processes and that roof drains’ low points also do not change through final design and/or permitting revisions.