PTQ Q3 2026 Issue

Design and application of e-houses in petrochemical plants

An Indian petrochemical facility realised a 90-day project schedule reduction using a fully integrated prefabricated substation instead of traditional substations

Wang Xin CTCI Beijing

A prefabricated substation (e-house) delivers a fully integrated, factory-tested power distribution sys- tem that can reduce project schedules by 30-50% compared to traditional stick-built construction. By consolidating medium-voltage (MV) and low-voltage (LV) switchgear, power transformers, motor control centres (MCC), uninterruptible power supplies (UPS), and auxiliary equipment within a custom-engineered steel enclosure, this modular solution shifts about 80% of installation and testing work from the unpredictable field environment to the controlled conditions of the factory floor. For petrochemical projects, particularly those executed as engineering, procurement, and construction (EPC) contracts, this approach offers three distinct advantages. First, minimised site work significantly reduces exposure to weather delays and cross-trade interference, which are leading causes of schedule overruns. Second, factory-controlled assembly ensures consist- ent quality and workmanship, governed by standardised procedures rather than variable site conditions. Third, single-point procurement simplifies supply chain manage - ment, replacing the complexity of coordinating multiple vendors with a single, accountable interface. The following discussion further examines e-house com- position, core technical systems, and comparative benefits in detail, concluding with a case study from an Indian petro- chemical facility that realised a 90-day schedule reduction, thereby validating the substantial value proposition of this innovative approach. Concept An e-house is a fully integrated power transformation and distribution system housed within a custom-designed steel structure. Unlike traditional substations, which are assem- bled piece by piece on-site over many months, the e-house arrives at the project site as a complete, factory-prein- stalled, and pre-commissioned package. It is, in essence, a building designed specifically to house electrical equip - ment, with the building and its contents engineered as a single, cohesive system. A typical e-house integrates a comprehensive range of equipment, including: •MV switchgear and power transformers.

•LV switchgear and MCCs. •UPS and direct current (DC) banks. •Electrical monitoring and control systems (EMCS) •Interconnecting cables and busbars between internal equipment. •Auxiliary systems: heating, ventilation, and air condition- ing (HVAC), fire alarm and suppression, and internal/exter - nal lighting. The prefabricated substation concept emerged from modular factory design in the 1990s, when entire facilities began to be divided into dedicated production, process, and electrical modules. Today, this solution is known by various regional names: power distribution centre (PDC) in North America, power house in Australia, and e-house in Europe and other markets, but the core principle remains consistent: deliver a fully functional substation as a single, pre-tested module. For petrochemical plants, e-houses should be placed as far away from classified hazardous areas as practicable (as defined by API RP 505 or IEC 60079-10). If installa - tion within or adjacent to a hazardous area is unavoidable, the e-house should be designed as a positively pressurised enclosure in accordance with NFPA 496 to prevent ingress of flammable gases and ensure safe operation. For large‑capacity or oversize e-house solutions, the module may be split into multiple units for transportation. On-site re-assembly, reconnection, and recommissioning should follow factory-approved procedures to preserve system integrity and performance. The composition of an e-house can be broken down into its physical structure and the electrical equipment it con- tains, all supported by integrated technical systems (see Figure 1 ). Structural components The physical structure of an e-house is more than just an enclosure; it is a load-bearing steel framework designed to withstand the stresses of lifting, transportation, and operation. Structural design should comply with international build- ing codes and standards (such as IBC, Eurocode, ASCE 7, NBCC, and local building codes) to resist wind, seismic, and snow loads, as well as transportation-induced dynamic

PTQ Q3 2026