Engineering Express provides structural design evaluations of various types of mechanical equipment exposed to weather. There are four (4) evaluation types typically performed, each with their own benefits and limitations of use. This article explores each type and provides examples and summary of output.
Some notes to first understand:
- All tiers listed below include a ‘tie-down check’ -the fastening of the product to the host substrate for a given overturning / sliding force.
- Engineering certifications are rated to a limiting design pressure. This pressure can correlate to a variety of wind speeds, exposure categories, and terrains. While we can review individual installations on a site specific basis beyond our general responses which typically yield better results. We cannot guarantee structural performance above the wind pressure we rate though which can’t be determined until after our analysis. Helpful tools are offered to assist in finding the pressures for your projects.
- Depending on project specific requirements, a given evaluation option may or may not be acceptable for permit or your use case. We cannot guarantee acceptance of certain tiers listed by any municipality. We recommend speaking with the authority reviewing the reports in question to see which method or methods would be acceptable.
- Each of the below options are quoted on a case by base basis once we review the complexity and variations of the unit(s) to be evaluated.
- Our quotations also vary based on the availability of detailed information for each unit being evaluated. For more on what information is required, click here.
Tier 1 – Tie-Down Only
Provide structural sealed document illustrating (1) worst case unit, up to 80 in. longest side, as per provided unit information, to resist design wind forces on anchorage of unit to host based on minimum requirements of (1) applicable building code.
Base service includes substrate of concrete, steel, and aluminum.
This service only certifies that the mechanical unit will remain attached to its host substrate. The service does not include a complete integrity check (i.e. finite element analysis or testing) of the unit cabinetry, nor that any cabinetry component will not become flying debris during a high-wind event. Missile impact resistance is not included in base service, if required see Tier 4.
Sealed plans and site specific applications will also be made available directly to contractors via our online store as we do other AC manufacturers (see our EX Plan Store).
Tier 2 – Tie-down + Limited Integrity Check
Provide structural sealed document illustrating (1) 
worst case unit , up to 80 in. longest side, as per provided unit information, to resist design wind forces on anchorage of unit to host and connection integrity of cabinet components to the main cabinet based on minimum requirements of (1) applicable building code.
Base service includes substrate of concrete, steel, and aluminum.
This service certifies that the mechanical unit will remain attached to its host substrate, and that no cabinetry component will become detached during a high-wind event. Service does not check overall cabinet integrity (racking, excessive deflection, deformation, etc.), which some municipalities may require. Please refer to Tier 3/4 service options for complete cabinet integrity check (i.e. through finite element analysis or testing, respectively). Missile impact resistance is not included in base service, if required see Tier 4.
Sealed plans and site specific applications will also be made available directly to contractors via our online store as we do other AC manufacturers (see our EX Plan Store).
Tier 3 – Tiedown + Finite Element Analysis Integrity Check
Provide structural sealed document illustrating (1) worst case unit , up to 80 in. longest side, as per provided unit information and assembly file, (Parasolid, STP, or similar), to resist design wind forces on anchorage of unit to host and integrity of cabinet components based on minimum requirements of (1) applicable building code.
Service includes a given amount hours of review and error checking of assembly file. Client responsible to comply with modeled condition and submit all assembly files for review and error checking. This price assumes the model is suitable for review without errors in the file, or that all errors will take less than 2 hours to adjust. If substantial errors are found in the file, additional hourly fees will apply through a separate quote.
Base service includes substrate of concrete, steel, and aluminum.
The service certifies that the mechanical unit will remain attached to its host substrate, that no cabinetry component will become detached during a high-wind event, and that individual cabinetry components are within their allowable deflection/deformation limits. We cannot guarantee operability after a high-wind event. The allowable pressures you receive with Tier 3 may be lower than pressures received from Tier 2 because we must remain within the strength and deflection limits of component materials.
This service does not include integrity check through physical testing of the unit cabinetry, which some municipalities may require; refer to Tier 4 to obtain this. Missile impact resistance is not included in base service, if required see Tier 4.
Sealed plans and site specific applications will also be made available directly to contractors via our online store as we do other AC manufacturers (see our EX Plan Store).
Your cabinet can take only this force and deformation will be within acceptable limits. We cannot guarantee operability but deformation should be within the range where operability is possible. We check to see if a certain component is within yield strength.
Tier 4 – Tie-down + Testing of Cabinetry Check
Provide structural sealed document illustrating (1) worst case unit , up to 80 in. longest side, as per provided unit information, to resist design wind forces on anchorage of unit to host and integrity of cabinet components based on minimum requirements of (1) applicable building code.
Service includes creation of a test protocol to qualify the mechanical unit to resist desired loads (wind and/or missile impact). After the completion of testing, our office will evaluate the test report to create the TER based off the results. Operability of unit is not certified through this method unless coordinated separately with a certification entity (i.e. Miami-Dade Product Control).
Note: This is the only tier that may certify missile impact. Also, if a Miami-Dade NOA is desired, this tier must be chosen to be approved.
Base service includes substrate of concrete, steel, and aluminum.
Sealed plans and site specific applications will also be made available directly to contractors via our online store as we do other AC manufacturers (see our EX Plan Store).
Click here to start the discussion with Engineering Express about your evaluation report needs.
Last Update: March 30, 2021