Medical Vault at Stanford Removed Using Diamond Cutting
A medical linear accelerator (LINAC) is the device often used for cancer patients being treated with external beam radiation, a localized system of radiation delivery. It sends high-energy X-rays to the exact region of the patient’s tumor, which is beneficial because it avoids delivering radiation to the surrounding healthy tissue. The LINAC uses microwave technology to produce these high-energy X-rays that can be shaped as they exit the machine to conform to the specific shape of the patient’s tumor. The LINAC is placed in a vaulted room with thick, reinforced lead and concrete walls so that the X-rays are isolated and no one other than the patient is exposed to them. A radiation therapist can only turn on the accelerator from outside of the concrete vault, and the machine will only emit the radiation necessary for treatment once it is turned on from outside, making the risk of unintentional exposure to the X-rays very low.
At Stanford Health Care in Pleasanton, California, General Contractor Hensel Phelps was working on a solution to dismantle and remove the existing concrete LINAC vault while the hospital conducted business as usual. Hensel Phelps and Stanford Health Care had both previously worked with CSDA member Lombardo Diamond Core Drilling of Santa Clara, CA, and knew they could expect professionalism, accuracy and a successful job from the contractor. Lombardo was contracted to remove the existing 3,985-square-foot interior of the concrete accelerator vault in the busy and operating Stanford Health Care and put their expertise to work to complete the job skillfully and safely.
The Lombardo team decided that wire sawing and core drilling the concrete vault opposed to robotic or manual demolition would be best suited for this removal, as mitigating any loud concrete breaking or vibrating inside the occupied hospital was paramount. The concrete LINAC vault was located on the first floor of the hospital and was surrounded by patient rooms and the infant delivery room was directly above it on the second floor. A team of six Lombardo operators utilized a Hilti DS3015 Wire Saw and an ICS Pentruder 3P8 HF Wire Saw to complete the sawing component of the work, sawing the perimeter of the 3,985-square-foot vault. The Lombardo operators also used a Diamond Tech 12 GPM Hydraulic 4 speed motor and Diamond Products M-6 25 GPM White Motor Hydraulic Core Drill with EZ Cut Products diamond bits for the core drilling component of the removal.
The concrete vault was constructed with embedded 10’ x 10’ x 10” thick steel shielding plates, and the overall concrete structure ranged from 32-inches to 58-inches in depth. The two Lombardo concrete drilling operators drilled approximately (130) 2” diameter wire access holes and an additional (180) 8” diameter holes for the removal process, completing a total of approximately 1,500 lineal feet of core drilling. In addition to the extensive core drilling, Lombardo’s two wire saw operators cut 1,680 lineal feet of concrete to remove the concrete vault lid and wall sections of the LINAC in its entirety. All concrete sections were dismantled and sawcut into 2’ x 2’, 3’ x 3’ or 4’ x 4’ sections based on the overall thickness of the individual pieces and the weight capacity of the specific equipment used.
Lombardo’s safety management team provided a plan to the GC prior to mobilizing and brought in a structural engineering firm, FBA, Inc. to assist in composing the plan. There were concerns with the lid removal due to the limited access as well as conduit power lines. The existing KV480 conduit power lines that ran over the top of the concrete vault lid were the main power feed for the surrounding hospital operations and for very critical locations, including the pharmacy and Department of Pediatrics. However, the GC was able to support the power lines while the Lombardo team dismantled the concrete lid around them with no damage, injury or disruption to power.
The overall project was immense due to the limited work space and occupied hospital with patients and pedestrians in close proximity of the workspace. The Lombardo team cites the biggest challenge was that they were working under the infant delivery department. The team was monitored closely during the entire removal process by the Hensel Phelps Safety team and Stanford Health Care with specific maximum acceptable noise decibels with the threat of the entire project being shut down if it was surpassed. By utilizing the diamond drilling and sawing techniques, Lombardo was able to keep the overall noise abated and the project on track.
The general contractor, Hensel Phelps, and Lombardo worked closely on the entirety of this project from the early budgeting stages through to the final contracting phase. The Lombardo team provided a solution for the complexity of this project that satisfied both the GC and the hospital. The methods and procedures utilized during this project were approved by both the owner and client prior to the dismantling process.
The vault dismantling and removal project by Lombardo was completed safely and on time. They continue to have a working relationship with the general contractor, Hensel Phelps. Lombardo is also a preferred vendor for Stanford Hospital Facilities and Stanford University Campus. The Lombardo team was very satisfied with the outcome of the project. Their skilled concrete drilling and sawing operators were able to complete this project swiftly and with zero injuries or safety issues, which is always the most important part of these tricky projects.
Project leader Jason Saiz said that he believes Lombardo was chosen for this project for their reputation for finishing jobs on time, as well as their trustworthiness. Saiz said about this project, “Lombardo Diamond Core Drilling, Inc. was elected to complete this project based on our great reputation. Our talented team of diamond operators have been providing concrete sawing and drilling services for contractors here in the Bay Area for 60 years.” CSDA takes pride in representing contractors that are respected and utilized in communities because of their character. Lombardo is a longstanding member of CSDA and encompasses the CSDA mission of having the highest standards of safety, quality and integrity.
Established in 1961, Lombardo Diamond Core Drilling, Inc. has been in business 60 years. They offer a wide array of services, including GPR scanning, utility locating, core drilling, slab sawing, wall sawing, wire sawing, robotic breaking, demolition and excavation. They have a fleet of 40 trucks that services the greater Northern California Bay Area. Their company strengths are all aspects of concrete sawing and drilling. Lombardo has been a member of CSDA for 50 years. President Richard D. Long was one of the founding members of the association.
General Contractor: Hensel Phelps
CSDA Contractor: Lombardo Diamond Core Drilling, Inc.
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Methods Used: Core Drilling, Wire Sawing