Every Size, Every Stakeholder, Verified Once: Inside a Press Gate Valve Model
Author:
Alex Crease
Why Multi-Product EPD Programs End Up Running on Copies
If you produce EPDs for a product family, the expensive part is rarely the first model. It is everything that happens after it. Each new size, material grade, or facility gets its own copy of the model, every copy has to be corrected separately, and every copy goes back to the verifier as if it were new.
This post walks through a different way to run that work, using a real CarbonGraph model of a press gate valve. It shows three things:
How one maintained model produces results for every configuration.
How the same model is shared with modelers, client analysts and the verifier, each with the right view.
What "verified once" means in practice, and what it does not mean.
The short version: one maintained model can produce every result you need, be shared with every stakeholder by role, and be verified once.
What Goes Wrong When Every Product Gets Its Own Model
Most products in a family share the same materials, processes and methodology. They differ in a handful of parameters: a body material, a casting weight, recycled content, the electricity mix at a particular plant, a transport distance.
Copying the model for each product feels like the safe choice, and it is fast the first time. The cost shows up later:
A correction made once has to be made everywhere. A fixed emission factor or a revised allocation rule must be applied to every copy, by hand, and any copy that is missed now disagrees with the others.
Results reach analysts and verifiers outside the model. Spreadsheets, PDFs and screenshots travel by email, and the reviewer sees outputs rather than the logic that produced them.
Verification repeats. Each copy looks like a new model, so each one is reviewed as a new model.
For an LCA consultancy serving several manufacturers in the same product category, the problem compounds: the same structure gets rebuilt for every client.
Inside a Press Gate Valve Model: One Baseline, Many Variants
The press gate valve model is built once, with a Baseline that holds the shared structure: the bill of materials, the manufacturing steps, the PCR-aligned system boundary and the parameter values common to the family.
Each product configuration is a Variant. A Variant stores only the values that differ from the Baseline, and inherits everything else. In the valve model, that looks like this:
One Variant per size, from DN15 (1/2 in) to DN65 (2-1/2 in): each overrides four values, the body mass, valve diameter, wall thickness and total mass.
DN80 (3 in): matches the Baseline, so it carries no overrides at all.
Because Variants inherit from the Baseline, a correction to the shared logic is made once and reaches every Variant. Each Variant keeps its own differences, calculates its own results, and can be exported on its own.
Variant or scenario? A Variant is a saved, versioned configuration that others can rely on. A scenario is a temporary "what if" that starts from the Baseline or a Variant without changing it. Analysts can explore scenarios freely without touching the configurations the EPDs rest on.
Who Sees What: The Modeler, Analyst and Verifier Views
The same model is shared with everyone who needs it, and each person sees it through their role.
The modeler maintains the Baseline and the Variants. They own the structure, the data and the methodology choices.
The client's analyst works inside the model rather than with an export. They can switch between Variants, read results and run scenarios without changing the model the EPDs depend on.
The verifier gets Analyst access, the same level as the client's analyst, and reviews the model itself: its structure, its data sources and its logic, not a set of screenshots of outputs.
Sharing is enabled on request. Teams that want it reach out to CarbonGraph, and it is switched on for their workspace.
What "Verified Once" Means in Practice
"Verified once" is easy to overstate, so it is worth being precise. It works today in two forms.
The verifier reviews the baseline model once inside the shared model, and only variant inputs need checking. Because every Variant inherits the reviewed structure, later Variants are a check of the values they override rather than a fresh review of the whole model.
SmartEPD templating verifies a template and reference EPD in a single pass and checks variant EPDs against its constraints. In Smart EPD's own words, "the template and its Reference EPD are therefore verified together, in a single pass." Variant EPDs are then validated against the template's bounds when they are generated. You can read how that works in Smart EPD's templating documentation.
Neither form is a guarantee of a verification outcome. The verifier still decides. What changes is how much of the work they have to repeat for each product.
At ACLCA 2026, one of our partners, Trinity Consultants, presented their work for their client Nucor in a session with Nucor and Smart EPD. Trinity walked through how they built an enterprise-wide parameterized model on CarbonGraph, shared it with their verifier, had it verified once, and then used it to create outputs for many of Nucor's products and facilities. Smart EPD showed how verified results become publishable EPDs through automation.
What This Changes for LCA Consultancies
The same pattern scales beyond one manufacturer. A consultancy can build an industry model: one model of a product family that it maintains once. Each manufacturer sends its own data for ingestion and receives its own model, shared with them by role.
That changes the economics of the work. Instead of rebuilding a similar model for every client in a category, the consultancy maintains one well-reviewed structure and spends its time on what clients pay for: the data, the interpretation and the decisions that follow.
A Better Way to Run a Multi-Product EPD Program
CarbonGraph is a next-generation LCA platform that helps organizations move from product data to verified environmental disclosures in a single, structured workflow. Variants and role-based sharing are how that workflow scales from one product to a family, and from one manufacturer to many:
One maintained model with a Baseline and Variants, so a correction reaches every product.
Sharing by role, so analysts and verifiers work in the model rather than with exports.
Verification that builds on what has already been reviewed, in the two forms described above.
If you run EPDs for a product family, or you are a consultancy that keeps rebuilding the same model for different clients, the useful next step is to look at one of your own families this way.
Book a working session and we'll scope an industry model for one product family with you. Book a working session
The point to take away: the cost of a multi-product EPD program lives in the copies. One maintained model, shared by role and verified once, removes them.