How MEP Engineering Adapted a Paris Baguette Bakery Cafe to an Existing California Building

Project Overview

The project involved converting a 2,500 sq. ft. existing commercial space in California into a Paris Baguette bakery cafe. The franchise layout had to fit within an existing commercial shell with limited basement space, existing building services, and restrictions on new exhaust routing.

The MEP engineering design needed to work around what the building already provided while meeting the franchise requirements. This included integrating a landlord-provided condenser water system, routing new HVAC through an occupied ceiling zone, and finding a practical solution for grease waste and kitchen exhaust.

The goal was straightforward: develop an efficient, code-compliant MEP design that worked within the existing building without introducing unnecessary construction.

The Challenge

Establishing Existing Conditions and Building Infrastructure

The available shell drawings, MEP documentation, site photos, and landlord information had to be reconciled to establish the actual utility connections and existing services.

This was important because the new MEP engineering services had to connect into the building's existing infrastructure. The HVAC system, for example, needed to use the landlord-provided condenser water system and match the available system requirements.

Working Within Limited Space

The basement had limited available space and also served as parking. The required grease interceptor therefore had to fit without reducing parking.

Above, the ceiling zone already contained existing services. New HVAC ductwork had to be routed through the remaining space while maintaining the finished ceiling height and avoiding conflicts.

Managing Fryer Exhaust and Construction Cost

The original gas fryer configuration would have required a Type I grease hood and a substantial vertical grease duct routed to the roof. Because a residential unit was located above, a Pollution Control Unit would also have been required.

This made the arrangement impractical and expensive. The MEP design therefore needed to consider a different equipment configuration rather than simply finding a way to route the original exhaust system.

Connecting to Existing Systems and Exhaust Routes

The new water-source heat pump had to connect to the landlord's condenser water loop while matching the available flow and pipe sizing.

Kitchen exhaust presented another constraint. The design needed to use a sidewall termination and outdoor air intake while maintaining the required clearances and working within the restrictions on new exhaust routing.

The MEP Engineering Approach

Making the Basement Work

A compact hydromechanical grease interceptor was selected for the limited basement space. A downstream sump pump lifted the treated waste to the building sewer at grade.

This avoided reducing parking and also limited the need for excavation and structural modifications. The solution demonstrated how MEP engineering services can adapt plumbing infrastructure to the physical conditions of an existing building.

Routing HVAC Through the Existing Ceiling

The HVAC layout was developed around the existing ceiling services. New ductwork was routed through the remaining available space to maintain the finished ceiling height and avoid conflicts.

The water-source heat pump was connected to the landlord's condenser water loop, with the flow and pipe sizing coordinated with the available system.

Outdoor air intake and sidewall exhaust locations were also coordinated to maintain the required separation and clearances.

Rethinking the Kitchen Exhaust

The gas fryer would have required a conventional Type I grease hood with extensive vertical grease ductwork.

The fryer was changed from gas to electric, which allowed the use of a listed ventless Type I hood and eliminated the need for the large vertical grease duct.

A separate Type II exhaust system was provided for heat and non-grease vapors from the fryer, deck oven, and convection oven. Where permitted, the exhaust was routed horizontally to an approved sidewall termination.

This equipment change became an important part of the HVAC engineering strategy because it addressed both the exhaust constraint and the construction implications.

Project Journey

Stage 1: Review and Design Development

The project began with a review of the existing shell drawings, MEP documentation, site photos, and landlord information. The design was then developed around the franchise layout, existing building infrastructure, and equipment requirements.

Stage 2: Engineering Optimization

The grease-waste arrangement, HVAC routing, and kitchen exhaust strategy were evaluated for practical, code-compliant solutions.

The HVAC design services focused on working within the existing ceiling conditions, while the plumbing design addressed the restricted basement space.

The fryer configuration was also reconsidered to avoid the extensive exhaust infrastructure that the original gas arrangement would have required.

Stage 3: Final Coordination

The mechanical, electrical, and plumbing systems were coordinated with the existing building services, landlord infrastructure, and project requirements to produce the final permit-ready design.

The completed MEP design allowed the new restaurant systems to fit within the existing building rather than requiring major changes to the building itself.