When you first encounter UniClass 2015, the biggest challenge isn't searching for codes… it's understanding what the different hierarchies actually mean.
It took me a year just to hear about UniClass has a hierarchy and realize I needed to implement it on my projects. Then another few months to truly understand how Pr, Ss, and EF work together.
If you're struggling with this, you're not alone. Let me break it down.
The Core Concept: Three Ways to Describe the Same Thing
UniClass uses different "tables" (hierarchies) to classify building components depending on your perspective:
- Pr (Products) - What you can buy or specify
- Ss (Systems) - How things work together functionally
- EF (Elements) - Physical components in the building
The same piece of equipment can have three different codes depending on which lens you're looking through.
My Go-To Analogy (It's Terrible, But It Works)
I explain this to teams using a motorcycle analogy:
Imagine you're going home after work. The function (EF) of going home is simply "going home." The system (Ss) you use to get home is a motorcycle. The product (Pr) within that system is you, the rider.
A Construction Example That Actually Makes Sense
Let's take an air handling unit in a building:
- Pr (Product): The physical air handling unit you purchase and install, the tangible piece of equipment you can touch on site
- Ss (System): The air conditioning system that the unit belongs to, the complete functional system providing cooling
- EF (Element/Function): Ventilation, the building function this system delivers
So if you want ventilation in your building, you achieve it through an air conditioning system, which requires an air handling unit among other components.
When Do You Use Each One?
- Procurement and purchasing? Use Pr (Products)
- System design and functional requirements? Use Ss (Systems)
- Building performance and facility management? Use EF (Elements/Functions)
The hierarchy you choose depends on what question you're trying to answer.
Still confused? Try UniClass Wizard to search across all hierarchies at once. You can also select what category to search.
