Your Guide to Enhancing MEP Drawings and Detailing using BIM

Challenges of traditional methods (CAD based) used for MEP drawings

CAD-based MEP drawings come with their own set of challenges that include:

• inability to identify clashes due to lack of visualization and coordination between services
• constant re-design and re-work due to interdisciplinary errors and coordination issues
• cost and time overruns due to rework
• inferior coordinated design quality due to traditional CAD processes

BIM helps contractors, design and engineer the MEP and building layout, wherein project visualization helps foster collaboration between architectural and structural teams.

Importance of MEP drawings in building construction

MEP coordination harmonizes various building services with other trades to form a strong foundation for onsite construction. Once the MEP coordinated drawings are prepared by the BIM MEP consultant, it is the MEP contractor’s responsibility to carry out detailing, fabrication, and installation.

Facilitates better design fabrication, installation and schedule

MEP drawings in building construction enable better fabrication, installation, and schedule as they are coordinated between mechanical, electrical, and plumbing teams.

Fabrication-ready MEP drawings help contractors create precise HVAC, electrical, and plumbing systems based on a complete drawing set. These drawings act as a quick reference source for contractors to assess the conditions of a building system and resolve onsite ambiguities. Contractors and engineers gain seamless onsite installation.

Reduces installation time for contractors and engineers

With scaled outlines of installation systems based on precise dimensions, connections, and accessories, contractors and engineers can carry out seamless installation. Contractors and engineers have a clear picture of what needs to be built, fabricated, and installed. With precise locations marked in MEP drawings, contractors can save on time through consistent and reliable onsite installation.

Hitech CADD Services created a 3D MEP BIM Model for a commercial building in the US, as per international standards. The coordinated MEP components generated better insights and saved significant time by eliminating clashes at initial stages of design.

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Ensures uniformity in sizes and modules across MEP systems

Coordinated MEP drawings improve uniformity and building performance by enabling standardization of MEP systems. Uniform building guidelines allow project stakeholders to stay on the same page while helping contractors easily obtain construction permits and licenses.

Generates precise cost estimates

With MEP coordination drawings in place, contractors can conveniently get component and material costs. This helps streamline supply chain, reduce material wastage, lowering construction costs and improving planning activity.

How coordinated BIM models enhance MEP drawings

While traditional MEP drawings begin in the later stages, BIM-led MEP coordination begins in the early stages of the project lifecycle. BIM has proved to be a crucial differentiator in the creation and application of MEP drawings. A BIM-based approach makes drawing and detailing far more precise, detailed, and reliable.

Precise information

Information accuracy of BIM-based MEP drawings is highly precise. A well-coordinated BIM model packs in every piece of information at various LOD levels.

MEP BIM models are developed at various LOD levels such as:

• Preliminary design models at LOD 100
• Detailed design models at LOD 200
• Construction design models at LOD 300
• Prefabrication model at LOD 400
• As built model at LOD 500

Hitech CADD Services created a coordinated 3D MEP BIM model with LOD 300 for a hospital building in Australia. The clash free plumbing layout and hydronic equipment for architectural and structural disciplines resulted in seamless installation detailed drainage systems for underground as well as upper floor drainage systems.

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3D MEP BIM model at LOD 300

With each increasing Level of Development, the depth of information becomes detailed and far more precise. Various prefab components and assemblies can be prefabricated based on detailed MEP fabrication drawings. These include sprinkler systems, vertical risers, plant modules for compressors, etc.

Clash- free models

3D BIM models are integrated by collaborating disciplines such as architecture, structure, and MEP. Once coordinated and clash-free, these models provide precise and trusted documentation. Contractors can pull these drawings from BIM authoring software like Revit® in various formats such as DWG, PDF, etc. An interference-free MEP drawing makes the onsite installation of various Mechanical, electrical, plumbing and fire protection systems quick and seamless.

Hitech CADD services created a clash free 3D model in Revit at LOD 400 and MEP coordination drawings for an airport project in Muscat. Clashes were identified and resolved using Navisworks®. A collaborative approach helped the client save $7 million in 6 months, and 100% of MEP systems were installed with minimal change orders based on reduced field conflicts.

BIM Clash Detection

Clash Resolution

Conflicts Checking

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Precise material-takeoffs and schedules

Based on a coordinated and information-rich BIM model, detailed schedules and material takeoffs can be generated for offsite fabrication and onsite installation. BIM MEP shop drawings can be leveraged by fabricators to build equipment, whilst precise schedules reduce material wastage and mitigate construction delays.

Better coordination leading to reduced RFIs

RFI’s generally arise when teams require additional information or clarification, or when problems are identified, or a modification is needed. Contractors or sub-contractors submit RFI’s to designers or engineers for drawing clarification, or if there may be concerns about specific building materials, component substitution, etc.

The time to create and receive RFI feedback can be time-consuming causing some parts of construction to be delayed. Every ambiguity is cleared early on in the design stage due to the increase in coordination, resulting in fewer RFI’s being raised. This reduces construction costs, boosts project efficiency and increases turnaround time.

BIM enables informed decisions to be taken

With every contractor or subcontractor looking at a single source of truth, proactive decisions can be taken to make onsite MEP installation quick and hassle-free. A well-coordinated MEP drawing can save in the thousands, and spin-up projects faster. An informed team can draw better scalability, flexibility, quick turnarounds, and lower overhead costs.

Hitech CADD Services created a coordinated 3D MEP BIM model for an institute in Europe with error-free GA drawings and spatial arrangement of the entire plant room- including equipment, connections and arrangement.

The 3D MEP BIM models helped the client easily detect and resolve clashes, make smarter and informed decisions, while saving construction cost with first time right deliverables.

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3D MEP Modeling Revit

Types of MEP drawings

MEP drawings are classified into 5 general categories such as penetration drawings, shop drawings, spool drawings, coordination drawings and as-built drawings.

MEP systems penetrate floor and wall spaces in the building. Penetration drawings assist contractors and onsite personnel to ensure penetration precision based on precise dimensions. Penetration drawings also assess the structural integrity of buildings and structures to check for future problems.

Shop drawings are crucial for MEP systems and equipment where dimensional accuracy is a necessity. MEP drawings need to account for finer details, manufacturing dimensions, and specific instructions.

Coordinating MEP systems help identify and resolve MEP collisions. Coordination drawings enable identification and resolution of clashes to minimize mistakes, cut-down on manufacturing costs and mitigate time overruns.

As-Built MEP drawings help update MEP systems, promote smooth renovation, and enable precise documentation. As-Built documentation also accounts for modifications done in the initial MEP plans.

Pipe spool drawings are required to manufacture customized and dimensionally precise spools for smooth plumbing installation.

Leveraging technology with automation

BIM will continue to become robust with automation tools. Automating MEP designs using Dynamo, APIs, and other plugins will ensure success in onsite construction.

• Dynamo-based parametric designs will help coordinate spaces and build family information as a data coordination tool amongst spaces and elements.
• Automated Revit MEP tools help calculate mechanical loads based on industry standards coupled with a quantity survey plugin to calculate material quantities.
• Customized Revit plugins can be used to add information systematically for each MEP element for the output to conform to industry standards.
• Dynamo can be used to automatically choose equipment capacity, cooling and heating load, correct piping size, etc. based on room specification information.