Designers and manufacturers create building products based on how they think people will use them and conditions they will resist through their life cycle. To create a product that is safe and easy to use, one requirement is to determine the product’s performance in various weather conditions in conformance to applicable federal, state and local codes and referenced standards.
How can a structural engineer help you?
Let’s say you are a HVAC (heating-air conditioning) manufacturer and you have created a new product component that will be placed outdoors. As a manufacturer you wouldn’t know that there are several Building Codes and local municipalities rules that enforce the analysis of the cabinet to ensure the integrity under in this case storm conditions, For example: Florida Building Code 1620.6 (2017) – Wind resistance of Mechanical Equipment.
Engineering Express will analyze your cabinet and prepare a Technical Evaluation Report (TER). See more on TER’s by clicking here
Here’s a summary of checklist items that we will need to begin your product evaluation. Be advised this is an iterative process that we will be consulting with you throughout the evaluation of the product and may require samples, field visits, testing, and other detailed information on parts and materials to complete our design.
Checklist for Mechanical Unit Product Evaluation / Assembly of Unit
- Provide information regarding the constructed unit assembly and how the assembly was fabricated.
- Table of all sizes and weights for the comparable model number(s)
- Provide detailed drawings of the unit showing
- Dimensioned section profiles
- Panel arrangement
- Installation and spacing of anchorage
- Door or access panel locking arrangement
- Product markings and their location
- …And any other pertinent construction details
- STP and/or DWG files (all structural components in it, no mechanical parts needed) – For SolidWorks/CAD
- Properties of all the hardware used and enclosure
- Provide information regarding the final product
- Target Height or pressure to be used with the evaluation
- How would you like to set up the report: based on installed height or based on maximum wind load pressures?
- Provide information on the type of steel used in the cabinets, and strength (or let us know to use a conservative assumption, based on past experience).
- Sheet metal screws on the unit, size, and material information (as well as strength)
- Drawings with exploded views of the cabinets, and drawing of the panels (internal components do not need to be shown); please make sure that the drawings have the material and thickness of each part.
- If your units need some kind of remediation, are you open to the use of straps?
- Would you like to have different tiers for height or just worst condition? See the image below which shows different tiers for height. The worst condition would simply be “Rated for X psf”
You can see we have a lot of information to obtain from you. If you had a detailed Solid Works or compatible 3D file, we could learn a lot from that. please send one over for our review. When you look at the spreadsheet above, you see we need to know important items for calculations like screw & washer information, placement, type of screw, frame thicknesses, etc. If you had a detailed parts list or exploded views that we could decipher without too much difficulty, we could gather what we need, such as something like this:
We’ll likely mark up the PDF’s you send to ask specific questions, like this:
Different Products Have Different Checklists
At the end Engineering Express and the TER we will provide, wind capacity rating, anchorage method to different substrates for the maximum wind rating and all the models that were analyzed.
What evaluating methods do we use at Engineering Express?
Before the beginning of the project, we’ll make sure of walking you through the options available to evaluate your project. Here’s another example. Let’s say that this time you are a Generator manufacturer that produces enclosures, we’ll let you know the existing methods to evaluate your product allowed by the American Society of Civil Engineers Standard 7, we can either go testing in laboratories the product or rational analysis like performing FEA analysis, SolidWorks evaluation, MEPLA study, Excel calculations, or any combination thereof.. it all depends on desired output, level of detail required, timeframe for the evaluation, and level of variation of answers desired in the report.
HVAC UNIT INTEGRITY STARTER CHECKLIST
Wind Load Demand
- Determine target wind velocity and roof height
- Determine target terrain exposure C or D
- Determine target wind pressure for lateral and uplift
- Determine panel tributary sizes
- Determine anchor quantity per panel
- For lid panels:
- Calculate typical anchors in tension or shear based on uplift
- Check if any anchors share both tension and shear requirements based on combined lateral + uplift loads
- Provide additional anchorage to panels where they are needed to resist loading
- Any cleats or “trapped” conditions are assumed OK
- If cables are being used for the restraint system:
- The frame does not need to be checked for overturning or uplift
- Calculate that the required shear does not exceed the frame’s connection to the base
- For unit panels where a frame exists:
- Calculate typical anchors in tension based on lateral pressure
- Spot check connection of internal frame to the base pan based on uplift and shear from overturning
- For unit panels where a frame does not exist:
- Calculate typical anchors in tension based on lateral pressure
- Calculate shear required by anchors which resist panel overturning
- Check if any anchors share both tension and shear requirements based on combined wall pressure and overturning loads
Base Pan Design
- Determine how base pan is attached to the base rail of the unit
- Check shear due to overturning and uplift for the anchors that attach the base pan to the base rail
- Provide additional anchorage to base pan and panel connections they are where needed to resist loading
- Determine restraint locations and connection method
- Design restraints for shear/tension in all anchors to the host structure
- Design of the host structure is not included
- Check ground conditions for 3000 psi concrete structure + any client requests
- Check rooftop conditions for 1/8” aluminum 6061-T6 or 1/8” steel A36 + any client requests
- Determine at what wind pressure no remediation is needed and report this
- Report ground mounted and roof-mounted maximum allowable pressures, and any additional anchors to be added
What Types of Products does Engineering Express Evaluate?
Our earlier examples were about mechanical equipment manufacturers, but that only was (1) of the segments we work for, we currently evaluate products for:
- Windows & doors
- Flood & Impact components
- Aluminum products
- Mechanical equipment – tanks, towers, poles
- Sunrooms, Patio Enclosures
- Decks, Roofing, Solar Equipment
- Signs, Billboards, Scoreboards
- Specialty components such as bank teller machines, propane gas tank holders, Public lockers, ride-sharing devices, and everything similar
What should you do next?
ADDITIONAL TOPICS IN OUR KNOWLEDGE BASE ON THIS SUBJECT:
Last Update: June 26, 2021