Aspen ACCE Guide

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Aspen Capital Cost Estimator (ACCE) is a model-based cost estimating tool for process and manufacturing plants. It builds estimates from equipment lists and process simulation outputs rather than manual quantity takeoffs. Best suited for projects where process equipment and utilities represent >30% of TIC — chemical, petrochemical, food/beverage, pharmaceutical, and water treatment.

This page covers how to actually build a Class 3–5 estimate in ACCE, including inputs, output interpretation, and common calibration issues.

When to Use ACCE vs. Other Tools

Situation	Use ACCE	Use Sage/RSMeans instead
Process-heavy plant (>30% TIC in process equipment + piping)	Yes	No
Building-dominant scope (office, shell building, light mfg)	No	Yes
Class 4–5 feasibility on a process facility	Yes	Possible, but ACCE is faster
Class 2–1 GMP / bottom-up	No — use ACCE for validation only	Yes
Brownfield tie-in to existing process system	ACCE for new scope, manual for tie-ins	Tie-in scope manually
Pharmaceutical cleanroom fit-out	Only for utilities/process; civil/arch by RSMeans	Yes for civil/arch/MEP

Core Workflow: Building a Model

Step 1 — Create a New Project

In ACCE, each estimate is a Project. Set:

Project name and number
Currency (USD; set exchange rate if multi-currency)
Estimate class (Class 5 / Order of Magnitude through Class 2 / Definitive) — this affects which escalation and contingency defaults ACCE applies
Pricing date — the date from which costs are indexed; update this to the current quarter to get current pricing

Step 2 — Set Location Factors

ACCE uses a location factor relative to the U.S. Gulf Coast (USGC = 1.00). Apply it in the Project Settings before adding any components:

Region	Approximate ACCE Location Factor
U.S. Gulf Coast (benchmark)	1.00
U.S. Midwest	1.05–1.10
U.S. Northeast	1.15–1.25
U.S. Southeast	0.95–1.05
Canada (Alberta)	1.25–1.40
Mexico	0.75–0.85

Important: ACCE location factors cover labor and bulk material costs. They do not account for site-specific conditions (remote site logistics, congestion premiums, local union jurisdiction rules). Add a separate site factor for those.

Source: ACCE location factor database, updated quarterly by AspenTech. Cross-check against ENR CCI regional data.

Step 3 — Define Process Components

ACCE estimates are built from components, each representing a piece of equipment or system. Three input methods:

Method	Use When	Accuracy
Equipment sizing (ACCE sizes from process parameters)	Early feasibility; process not fully defined	Class 5–4
Equipment list (you supply equipment specs)	FEED or later; equipment list exists	Class 4–3
Mapped from process simulation (Aspen Plus / HYSYS link)	Full simulation model available	Class 3–2

For a manufacturing plant estimate without a simulation model, Equipment List method is the standard:

For each piece of process equipment, add a component and select the equipment type (heat exchanger, vessel, pump, compressor, reactor, etc.)
Enter sizing parameters: capacity, material of construction, design pressure, design temperature
ACCE calculates a free-on-board (FOB) equipment cost using internal cost curves

Step 4 — Review Equipment Costs

ACCE’s built-in equipment cost curves are based on vendor quote databases updated by AspenTech. Before relying on them:

Cross-check 2–3 major equipment items against recent vendor budgetary quotes
Note the ACCE accuracy range — equipment cost curves can vary ±30% from actual quotes for non-standard equipment
Exotic metallurgy (duplex SS, Hastelloy, titanium): ACCE may underestimate — apply an alloy surcharge factor (typically 1.5–3.0× carbon steel price depending on alloy and form)

Step 5 — Apply Installation Factors

After ACCE calculates FOB equipment cost, it applies installation factors (similar to Lang/Hand) to estimate installed direct cost:

Account	ACCE Factor Applied To
Equipment erection	Equipment cost
Piping (process)	Equipment cost × piping complexity factor
Instrumentation	Equipment cost
Electrical	Equipment cost
Civil / structural	Equipment cost + area-based factors
Insulation and painting	Piping and vessel cost
Indirect costs (engineering, procurement, construction management)	% of direct cost

Piping complexity factor is the most sensitive input. ACCE uses a default piping complexity based on project type — override it if you have project-specific information:

Simple (low pipe density, few specialty fittings): 0.4–0.6
Average (typical process plant): 0.7–1.0
Complex (high-pressure, exotic metallurgy, tight spacing): 1.1–1.5

Step 6 — Add Bulk Materials and Civil Scope

ACCE handles process components well but handles civil/structural and building scope poorly. For a manufacturing plant:

ACCE for: process piping, process electrical, process instrumentation, process vessels and equipment
RSMeans / manual estimate for: foundations (if not covered by ACCE civil defaults), building enclosure, architectural finishes, site work, fire suppression, non-process HVAC

Run both models in parallel and combine in a summary spreadsheet. Do not let ACCE’s civil defaults substitute for a real civil estimate on a building-heavy scope.

Step 7 — Review the MTO Output

ACCE generates a Material Take-Off (MTO) alongside the cost estimate. Use it to:

Verify that pipe quantities and fittings counts look reasonable vs. P&IDs
Check that instrumentation count matches the instrument index
Catch configuration errors (a vessel showing 0 nozzles, a pump with no piping connections)

If the MTO looks wrong, the cost will be wrong. Fix the model inputs, not the cost.

Step 8 — Apply Contingency and Escalation

ACCE has built-in contingency defaults by estimate class — review and override them:

Class 5: ACCE default ±50% → set contingency 30–50% (per AACE RP 18R-97)
Class 4: ±30% → set 20–30%
Class 3: ±20% → set 15–20%

Do not use ACCE’s escalation default. It uses a fixed internal escalation rate that may not reflect current market conditions. Override with ENR CCI or BLS PPI data — see Material Escalation and Commodity Pricing.

Output Interpretation

ACCE produces a cost report with this structure:

Account	Description
10	Equipment (FOB)
20	Equipment erection
30	Piping
40	Instrumentation and controls
50	Electrical
60	Civil / structural / architectural
70	Insulation and painting
80	Mechanical (HVAC, plumbing — limited)
90	Indirect costs (engineering, procurement, CM, startup)

TIC (Total Installed Cost) = sum of all accounts. Compare to $/SF or $/unit benchmarks from IPA or ISPE as a sanity check.

Common Output Mistakes

ACCE TIC ≠ GMP TIC: ACCE does not include owner costs, design fees, contingency (unless added), escalation (unless added), or contractor fee. Add these manually in your summary worksheet.
Accounts 80 (HVAC/plumbing): ACCE’s coverage is minimal — use a separate HVAC estimate for process HVAC.
Startup costs (account 90 sub-item): ACCE includes a startup cost estimate that is often understated for complex process startups. Validate against project-specific commissioning plan.

Class 3 vs. Class 5 Mode

Parameter	Class 5 Run	Class 3 Run
Equipment input	Capacity-based sizing only	Full equipment specification (size, material, pressure)
Piping	ACCE default complexity	Override with P&ID-based pipe count
Contingency	30–50%	15–20%
Location factor	Apply	Apply (should be same)
Expected accuracy	−50% / +100%	−15% / +30%
Purpose	Concept screening	FEED gate budget commitment

For Class 3, run a model calibration check before finalizing: compare 3–5 ACCE equipment costs against current vendor budgetary quotes and adjust if ACCE is systematically off.

Integration with Aspen Plus / HYSYS

If a process simulation exists, ACCE can import equipment sizing directly:

Export equipment list from Aspen Plus or HYSYS
Import into ACCE via the simulation link
ACCE reads operating conditions (T, P, flow) and sizes equipment automatically

Benefit: Eliminates manual data entry errors, keeps estimate in sync with simulation. Risk: Simulation equipment sizes are often preliminary — verify that design conditions match vendor data sheets before using simulation-driven ACCE as a Class 3 basis.

Estimating Software Guide — tool selection by project type and estimate class
Parametric Estimating Models — conceptual framework ACCE builds on (Lang/Hand, capacity scaling)
Pricing and Cost Assembly — how to combine ACCE output with civil/building estimates in the GMP hierarchy
Material Escalation and Commodity Pricing — escalation data to override ACCE defaults