W2.1_TH_Standardized WBS Structures for Gas Station Project

Problem Definition

One of the leading causes of claims and disputes on a project comes because of poor or incomplete scope definition; leading to scope changes and variations[1]. Standardized WBS structures can help the project team to deliver project objective with OTOBOS (On Time, On Budget and On Schedule). What kind of standardized WBS can be adapted for Gas Station (GS) Project?

Develop the Feasible Alternative

There are two best practice of standardized WBS[1]:

  1. NORSOK Standard Z-014: Standard Cost Coding System (SCSS) rev 1, Oct 2002. NORSOK was developed on 1989 because the Norwegian government was unhappy with all their production sharing contractors reporting costs using different coding structures.
  2. OmniClass: OmniClass is a means of organizing and retrieving information specifically designed for the construction industry. The concept for OmniClass is derived from internationally-accepted standards that have been developed by the International Organization for Standardization (ISO 12006-2) and the International Construction Information Society (ICIS) subcommittees and workgroups from the early-1990s to the present.

The author will compare both of them and choose one that most suitable for GS Project.

Develop of the Outcome for Alternative

The WBS is supposed to top down approach, become input for the CPM Schedule and also using Activity Based Costing.

Selection Criteria

Characteristics of the WBS:

  1. WBS is hierarchical
  2. WBS defines specific output
  3. WBS can give many point of view for management

Analysis & Comparison of Alternative

OmniClass consists of 15 hierarchical tables, each of which represents a different facet of construction information or entries on it can be combined with entries on other tables to classify more complex subjects[2].

Fig 1. Inter-related OmniClass[2]

Fig 2. OmniClass Table 21 (Elements) [3]

NORSOK standard describes a system for coding of cost and weight estimates and as-built/experience data. It comprises 3 sets of complementary sub-coding systems named:

  1. PBS (Physical Breakdown Structure)
  2. SAB (Standard Activity Breakdown)
  3. COR (Code Of Resources)

Fig 3. Norsok SAB (Standard Activity Breakdown) Elements[4]

We can compare both OmniClass and NORSOK as follow:

Fig 4. Comparison OmniClass vs NORSOK

Selection of the Preferred Alternatives

GS is construction project based, this project built facility to transfer gas from pipeline to transportation vehicle such as bus, truck, taxi, bajaj on Compression Natural Gas (CNG) form.

Since GS project is construction based that have zone breakdown structure, the Omniclass WBS will give more variations of WBS elements and can be implemented for standardize WBS into GS Project.

Performance Monitoring and The Post Evaluation Result

A standardized WBS structure is one success key for project team to the deliver project with OTOBOS. The next step will be to build up WBS for the Gas Station Project using top three elements of OmniClass, to prove whether the conclusion above is correct, and start evaluating the impact during phases of the project.



  1. Planning Planet (2017). Creating Work Breakdown Structure. Retrieved from http://www.planningplanet.com/guild/gpccar/creating-work-breakdown-structure
  2. Ardi, Satria. (2014). W14_SAS_Developing|Soroako AACE 2014. Retrieved from https://soroakoaace2014.wordpress.com/2014/12/12/w14_sas_developing-standardize-omniclass-3d-wbs-for-electric-furnace-rebuild-project/
  3. OmniClass (2017), OmniClass Table 21 – Elements (includes design elements). Retrieved from www.omniclass.org/tables/OmniClass_21_2012-05-16.zip
  4. Norsok Standard Z-014 (2017), Norsok Standard Z-014. Retrieved from http://www.standard.no/pagefiles/951/z-014.pdf
  5. Ardi, Satria. (2014). W12_SAS_Developing|Soroako AACE 2014. Retrieved from https://soroakoaace2014.wordpress.com/2014/11/28/w12_sas_developing-3d-wbs-for-electric-furnace-rebuild-project/