OEM Drawings and Field Verification: Closing the Information Gap

A layout drawing from an equipment manufacturer is not an engineered installation package, and treating the two as interchangeable is one of the more expensive mistakes an owner can make. Even with a strong site plan in place, an installation project can still run into serious cost and schedule risk if the drawings, the foundation design, and the as-built conditions were never fully verified.

Drawing Quality From an OEM Varies More Than Most Owners Expect

How much information the installation team gets from an OEM is inconsistent project to project. Some packages arrive with drawings detailed down to the individual piece-part level. Others show up with a handful of general arrangement drawings and not much else.

Often, the difference usually comes down to who hired the installer and what questions the buyer knew to ask from the OEM when purchasing the equipment. When the OEM’s own representative brings in the contractor, information tends to flow more freely, because the OEM has an interest in the installation going smoothly under its own name. When the owner hires the installer directly, the OEM has less incentive to hand over everything it knows, and the installer or end user bears the burden of determining and managing the assembly sequence from a much thinner information packet. Knowing which situation applies before signing a contract changes how much additional discovery time needs to be built into the schedule.

A Generic Layout Drawing Is Not a Foundation Design

This is also where foundation design gets missed most often. OEMs frequently attach a generic layout drawing with a note at the bottom stating that a professional engineer needs to be involved or that the buyer is responsible for verifying that the foundation is suitable for the machine’s installation, without the client realizing that the equipment they purchased still needs a foundation engineered and built underneath it. In some cases, that gap surfaces only after a significant piece of equipment has already been purchased, and the owner discovers a separate, unplanned expense for foundation design and construction.

Confirming this before the equipment purchase order is signed, not after, avoids a costly and uncomfortable conversation later in the project. A direct question to the OEM, whether the layout drawing has been engineered for this specific site or is a generic reference document, is usually enough to surface the gap early.

Field Verification Is Not a Formality

Skipping field verification, physically checking that as-built site conditions actually match the drawings before steel gets fabricated, is one of the costlier mistakes made on retrofit and tie-in work. A small surveying error, even a fraction of an inch at the anticipated datum point on a layout, can become a much larger misalignment forty or fifty feet away. Third-party engineering scans are usually accurate, but they can still turn out to be off once someone checks the reference points by hand in the field. Catching that discrepancy before fabrication begins is the difference between a minor correction and scrapping an entire structure that has already been built.

The same principle applies to existing equipment being removed from a facility. A rigging point that has held up for twenty or thirty years still needs to be inspected before it’s trusted again, since age and exposure change what it can safely carry, regardless of what the original design intended. Sometimes the safest method is to install new lifting lugs or cut new access into the equipment itself rather than rely on original rigging points that have been exposed to decades of wear and corrosion.

Put Assumptions About Weight, Packaging, and Configuration in Writing

Because installation estimates often rest on information that hasn’t been fully verified, experienced teams write their assumptions into the proposal instead of leaving them unstated. If a bid package quotes one total weight for a piece of equipment but past experience shows it typically arrives in several pieces at a lower per-piece weight, that assumption goes in writing, along with the expected configuration and condition on delivery.

That protects both parties in a agreement. It shows the client the team has handled comparable work before, and it sets a clear boundary for what happens if actual site conditions or equipment configuration turn out different from what was quoted.

What This Means for Planning an Installation

Before committing to a schedule or a budget, ask the OEM directly whether the drawings provided are engineered for the specific site or generic, confirm who is responsible for foundation design, and build field verification into the schedule before fabrication begins on any retrofit or tie-in work. Document assumptions about weight, packaging, and configuration in writing rather than leaving them as a verbal understanding. These steps take time up front, but they are far cheaper than the alternative of discovering a mismatch after fabrication has already started.

About the Author

Scott Walker serves as Millwright Division Manager for Wayne Brothers’ Industrial Group, bringing 35 years of construction and millwright expertise to the organization. In this role, Scott holds executive-level responsibility for project performance, overseeing all bidding and estimating activity while providing strategic leadership across projects and staff. His deep technical background combined with his management experience allows him to guide teams through complex scopes with a focus on quality, schedule, and client success.

Read the Guide on How to Prepare for Installation