Goal and scope

Goal and scope is the shortest phase to write and the one that most often decides whether a study is useful. Every later choice traces back to it.

The goal

ISO 14044 asks you to state four things unambiguously:

1. Intended application: e.g. “identify hotspots to prioritise redesign of product X”.
2. Reasons for the study: why now, and what decision it feeds.
3. Intended audience: internal team, customers, the public.
4. Whether results support comparative assertions disclosed to the public.

Write these first. They tell you how good your data must be and whether you’ll need a critical review.

The functional unit

The functional unit is the quantified performance of the product system that all results are expressed against. It describes what the product does, not what it is.

Weak	Better
1 kg of paint	Paint needed to cover 1 m² of wall at 99% opacity for 10 years
1 light bulb	1,000,000 lumen-hours of light
1 insulation board	1 m² of insulation with thermal resistance R = 5 m²K/W for 50 years

The better versions let you compare products that deliver the same function in different ways. A cheap paint that needs recoating every three years might use more paint over ten years than a durable one.

The reference flow is the amount of product needed to fulfil the functional unit. For the paint example: if paint A covers 8 m²/L and needs recoating every 5 years, the reference flow is 1/8 × 2 = 0.25 L per m² over 10 years.

Tip

Where an EPD or PCR applies, it often fixes the unit for you, sometimes as a declared unit (“1 tonne of cement”) rather than a functional unit, because the product’s final function isn’t known. Declared-unit results cannot be compared across products on their own.

The system boundary

The boundary says which unit processes are inside the study. Common scopes:

Cradle-to-gate

Raw material extraction through manufacturing, ending when the product leaves the factory. Typical for intermediate products (steel, cement, chemicals). In EN 15804 terms, modules A1–A3.

Cradle-to-grave

Adds distribution, installation, use, maintenance and end of life. Needed when use phase or disposal matters, which for energy-using products it almost always does.

Cradle-to-cradle

Cradle-to-grave with recycling loops back into new products. Often shown as a separate “benefits beyond the system boundary” result (EN 15804 module D).

Draw a flow diagram. Seriously: a box-and-arrow diagram of the product system catches missing processes faster than any checklist.

Cut-off criteria

You can’t model everything. Cut-off criteria say what may be left out, usually by mass, energy or environmental significance, e.g. “inputs below 1% of total mass may be excluded, provided excluded inputs together are below 5%”. State them in advance and check afterwards that nothing excluded turns out to be significant.

Allocation: when a process makes more than one product

A sawmill produces timber and sawdust. A refinery produces petrol, diesel and dozens more. How much of the refinery’s emissions belong to your litre of diesel?

ISO 14044 sets a hierarchy. Use the first step that works:

1. Avoid allocation, by either
   • subdividing the process into sub-processes so each output has its own data, or
   • system expansion: widening the boundary to include the functions of the co-products (often implemented as substitution, crediting the product the co-product displaces).
2. Allocate by an underlying physical relationship: partition inputs and outputs in a way that reflects how they change with the outputs (for example mass or energy content, where that is physically meaningful).
3. Allocate by another relationship, most often economic value.

Whatever you choose, apply it consistently to similar processes, and check how much the result depends on it (a sensitivity analysis). Recycling and end-of-life allocation have their own rules, which LCA 301 covers.

Common mistake

Jumping straight to mass allocation because it’s easy. It’s step 2 of the hierarchy, not step 1, and it can be badly misleading when co-products differ greatly in value.

Also part of scope

• Impact categories and LCIA method (Lesson 6).
• Data quality requirements: time period, geography, technology, precision, completeness, representativeness (Lesson 5).
• Assumptions and limitations, stated up front.
• Type of critical review, if any.

What you should now be able to do

• Write a functional unit and the matching reference flow for a product you know.
• Choose and justify a system boundary.
• Walk through the allocation hierarchy for a multi-output process.