Building – General contracting Class I; Petrochemical – General contracting Class I; Structural steel – Discipline contracting Class I; Public utilities – General contracting Class II; Electrical – General contracting Class III; Building Electro-mechanical installation – Discipline contracting Class I; Electronics and smart chemical engineering – Discipline contracting Class II; Fire-fighting facilities – Discipline contracting class II; Power transmission and transformation – Discipline contracting Class III; Special works (Special equipment lifting) – Discipline contracting