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MEP Design Calculations For U.S. Consulting Firms

Code-based calculations that support your MEP design, referenced against current U.S. mechanical and plumbing codes, delivered for your engineer of record’s review and seal, not as independent engineering output.

Design calculations are the part of MEP work that’s easiest to fall behind on and hardest to safely rush. Excelize’s team develops the code calculations that support your design, HVAC load calculations, sizing, and code-basis documentation, built to be reviewed against current U.S. mechanical and plumbing code requirements by your firm’s own licensed engineer before anything moves toward permit.

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2004Building BIM since
Costa Mesa, CAOnshore support
Mech + PlumbCode familiarity
EOR ReviewRequired
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Developed by us, sealed by your EOR What we deliver
What It Is

What are design calculations in this context?

Design Calculations are the numerical and code-reference work that supports an MEP design. Excelize’s team develops it. Your firm’s own engineer of record reviews, revises, and seals it.

This is distinct from Engineering Design Support, which covers the design development and drawings themselves. Calculations are the documented basis behind those drawings. They’re referenced against current code requirements for the project’s jurisdiction.

This is support work, not independent engineering. Nothing produced here is issued as final, sealed calculations. It always passes through your firm’s own licensed review first.

Where calculation work actually slows a project down

01

Confident drawings, unfinished code basis

A design team is confident in the drawings but behind on the documented code basis supporting them, and that gap becomes a plan-check delay when a reviewer asks for calculations the team hasn’t finished.

02

Calculations rushed at the end

Calculations get treated as a final, rushed step before submission instead of developed alongside the design, so late design changes mean re-running work that should have already accounted for them.

03

Licensed hours spent on drafting work

A firm’s engineers spend hours on calculation work that a supporting team could develop to a reviewable draft, when that time would be better spent on the engineering judgment only a licensed engineer can actually apply.

Each of these is the same underlying problem: calculation work developed to a reviewable draft by a supporting team frees your licensed engineer to do the judgment work only they can do.

What We Deliver

What our design calculations service includes

Code-Basis Confirmation

Confirm which code edition and jurisdiction-specific amendments apply to the project before calculation work starts, so the basis is right from the first draft, not corrected after review.

HVAC Load Calculations

Load calculation support for HVAC system sizing, developed to current code requirements and coordinated with the mechanical design and drawings developed alongside it.

Code Calculations And Documentation

Documented code calculations supporting mechanical and plumbing design decisions, referenced against current U.S. code requirements and prepared in a format ready for your engineer’s review.

Life Cycle Costing Analysis

Calculation support aimed at optimal life cycle costing, evaluating design options against cost and performance over the life of the system, not just initial installation cost.

Audits And Evaluations

Calculation-supported audits and evaluations of existing or in-progress designs, identifying where a system’s sizing or code basis needs revisiting before it moves further into design development.

CFD / FEA Analysis Support

Where a project’s complexity calls for it, computational fluid dynamics or finite element analysis support for airflow, thermal, or structural behavior modeling is scoped individually based on project need.

Codes & Standards

Codes and standards our calculations reference.

What the standard governs

HVAC design, energy efficiency, and ventilation standards that govern mechanical system design in the U.S.

Standard our team works with directly
What Excelize delivers
HVAC system design support
Ventilation & load calculations
Energy-efficiency-aware design
Ductwork sizing coordination
Reviewed under your EOR’s seal
Design and calculation support referenced against ASHRAE, delivered for your engineer of record’s review and seal. Explore Design Calculations →
What the standard governs

Fire protection and life safety system standards, from suppression layout to alarm and egress requirements.

Standard our team works with directly
What Excelize delivers
Fire protection design support
Sprinkler system coordination
Life safety documentation
Code-basis verification
Reviewed under your EOR’s seal
Fire-protection design support referenced against NFPA, coordinated with your engineer of record per project. Explore Engineering Design Support →
What the standard governs

Electrical system design and installation safety, the code basis behind every power and distribution layout.

Standard our team works with directly
What Excelize delivers
Electrical design support
Load & panel schedule calcs
Distribution layout coordination
Installation safety compliance
Reviewed under your EOR’s seal
Electrical design support referenced against NEC (NFPA 70), with your PE retaining full seal authority. Explore Design Calculations →
What the standard governs

Ductwork construction and installation standards, from gauge and reinforcement to hanger and seismic requirements.

Standard our team works with directly
What Excelize delivers
Ductwork design support
Construction-standard detailing
Installation-ready coordination
Reviewed under your EOR’s seal
Building and plumbing code compliance is also referenced against IBC, IMC, and IPC/UPC per your project’s AHJ — confirmed with your team at scoping. Explore Engineering Design Support →
Our Process

Our design calculations process

01

Code basis and scope confirmation

We confirm the applicable code edition, jurisdiction, and which calculations the project actually needs, like load calculations, sizing, life cycle costing, or a combination.

02

Calculation development

Our team develops the calculations against the confirmed code basis, coordinated with the design drawings, so the numbers and the design reflect the same current information.

03

Internal consistency check

Before delivery, we check the calculations against the design model for consistency, catching mismatches between what's calculated and what's drawn before your engineer's review does.

04

Delivery for engineer review

Calculations are delivered in your required format for your firm's licensed engineer of record to review, revise as needed, and seal; this step is where final engineering authority sits.

05

Revision support

We incorporate your engineer's revisions and re-run calculations as needed until the documentation is ready to move forward to permit.

How We Scope

Calculation support scoped to what your project needs

One-Project Calculation Package

A firm behind on plan-check documentation for one active project usually needs a focused calculation package developed quickly against a confirmed code basis, not a broad, open-ended engagement.

Standing Calculation Support

A firm managing several projects with a recurring calculation workload, HVAC sizing across a portfolio of similar building types, tends to benefit from a standing arrangement where calculation support scales with active project count rather than getting scoped one project at a time.

Life Cycle Costing Analysis

A firm evaluating design options against long-term cost needs the life cycle costing analysis specifically, which is a different calculation exercise than code-basis sizing alone.

Calculation capacity that scales with your projects

Onshore support is based in Costa Mesa, California, with calculation delivery capacity extended through an onshore and offshore hybrid model, so a focused package for one deadline or recurring support across several active projects both scale to what you actually need.

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FAQs

Design calculations FAQs

Still have questions? Talk to a BIM Lead
No. All calculations are developed for your firm's licensed engineer of record to review, revise, and seal. Excelize does not issue independent, stamped engineering calculations.
Our team works directly with ASHRAE, NFPA, NEC, and SMACNA standards for HVAC, fire protection, electrical, and ductwork calculations. Building and plumbing-specific codes are confirmed per project jurisdiction alongside your engineer of record.
Engineering Design Support covers the design development and drawings. Design Calculations cover the specific numerical and code-based work supporting that design. Many engagements need both to be developed together, so the drawings and the calculations stay consistent with each other.
Yes, that's a common starting point. We'll confirm the current code basis and design status first, so the calculations we develop match where the design actually stands, not an earlier version of it.
Generally, the current design drawings or model, the project's jurisdiction, and any code amendments specific to that jurisdiction. We confirm the full list during scoping.
Yes, on a scoped basis for projects where airflow, thermal, or structural behavior modeling is genuinely needed. This is scoped individually rather than offered as a standard package, since the depth required varies significantly by project.
This depends heavily on scope; a single system's load calculations move faster than a full building's code documentation package. The timeline gets confirmed once the scope and code basis are set.

Tell us what calculations your project still needs

A specific system, a full code documentation package, or ongoing support across several active projects each shape how this gets scoped. Send us where things stand, and a sample comes back in 2 to 3 days.

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  • No contract
  • No obligation
  • Your calculations and your IP stay yours
  • Your engineer of record retains final seal authority throughout
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