How Drawing Review Caught 5 Conflicts on a New Jersey Lab Conversion

Converting a Low, Wide Office Building in New Jersey Into Lab Space

A general contractor was converting an existing office building in New Jersey into lab space. The building was low and wide, with a steel frame designed for office use and part of the site in a flood hazard area.

A conversion runs on two sets of assumptions at once. The existing building was designed for desks and light partitions. The lab program brings freezer banks, autoclaves, imaging equipment, 100% outside air, fume hood exhaust, and bulk gases, and the lab planner's layout kept changing during design.

The GC wanted the reinforcement, the rooftop, and the site checked against the current lab layout before steel work began.

Helonic Found Lab Loads on Office Floors Before $200,000 to $800,000 in Field Reinforcement

The GC uploaded the PDF set, the specifications, the structural assessment, and the lab planning drawings. Helonic compared the existing building drawings with the new work, the lab layout with the structural reinforcement, and the MEP and civil drawings with the specs.

The first finding was office floors carrying lab loads. The existing drawings and the structural assessment on S-001 showed floors designed for typical office loading, roughly 50 psf live load plus a partition allowance, with a steel frame suited to office use and not to vibration-sensitive work.

The lab planning drawings on LP-201 placed -80°C freezer banks, an autoclave, and a microscopy suite on the second and third floors. The structural reinforcement drawings on S-201 strengthened only the bays where the lab planner's earlier layout had put heavy equipment. The layout moved, and the reinforcement did not follow.

Labs typically need 100 to 125 psf, and imaging equipment needs a much stricter vibration criterion than an office floor provides. Several bays now carried loads they had not been checked for, and the microscopy suite sat mid-span on a floor that would never meet its vibration spec.

Reinforcing existing steel after ceilings, ductwork, and lab casework are in means removing fireproofing, welding in finished or occupied areas, and moving MEP out of the way. If the vibration problem is missed, the tenant's microscope will not work and the suite has to move. The GC priced it at $200,000 to $800,000 for field reinforcement, MEP relocation, and layout changes, with 4 to 10 weeks of delay. Fixed before steel work, the analysis and reinforcement design were $10,000 to $30,000.

The second was lab exhaust that could re-enter the building. The mechanical roof plan on M-401 placed the new lab exhaust fans and the new 100% outside air units on the existing low roof. The spec section 23 38 16 required the exhaust stacks to meet the height and discharge velocity set by a wind wake dispersion study, so fumes clear the building.

The drawn stacks were shorter than the study required, and one new air handler's outside air intake sat about 25 feet downwind of the exhaust fans under the prevailing wind. A low, wide office building has a large rooftop wind wake, which makes re-entrainment more likely than on a purpose-built lab.

Re-entrained lab exhaust means chemical odors inside the building, and at worst evacuations and an unhappy tenant. Fixing it after installation means taller stacks with bracing, higher-velocity fans, or a relocated intake, each needing new support on an existing roof. The GC priced it at $50,000 to $250,000 in the field, with about the same cost after occupancy plus odor complaints. Fixed before construction, it was $5,000 to $20,000.

The third was critical equipment below the design flood elevation. The civil drawings on C-001 showed the site partly in a flood hazard area, with the state's design flood elevation noted. New Jersey tightened its flood hazard rules after recent major flooding, and the state elevation sits above the FEMA 100-year level.

Electrical sheet E-101 and the mechanical plans put the new main switchgear, the emergency generator, and the fire pump in the existing ground-level mechanical room, the obvious place for them in the old building. That room was below the design flood elevation. The state rules require critical equipment to be elevated above it or protected, and a lab has more critical equipment than an office: freezer and incubator power, exhaust fans that must keep running, and life safety systems.

This can stop the permit. Missed, the fix after installation means moving the switchgear and generator to an elevated platform or the roof, re-feeding the building, and redoing utility coordination. Being wrong means a flooded switchgear room and a tenant losing years of samples in failed freezers. The GC priced it at $300,000 to $1.5 million with 8 to 20 weeks of delay. Fixed before construction, it was $5,000 to $20,000.

The fourth was energy recovery that could cross-contaminate. The spec section 23 72 00 allowed energy recovery on the lab air handlers but required a run-around coil loop, or another method with no possibility of cross-contamination, on any exhaust that included fume hood air. The AHU schedule on M-601 listed units with enthalpy wheels, standard on office projects, recovering heat from the general lab exhaust, which the riser diagram combined with the fume hood exhaust.

Enthalpy wheels can carry a small amount of exhaust air, and the contaminants in it, back into the supply stream. That is acceptable for office air and not for fume hood exhaust. In New Jersey the energy recovery also carries a large share of the heating: 100% outside air at winter design temperatures near 10°F is a large load, so a less efficient system may need bigger preheat coils and freeze protection.

Lab air handlers are custom units with long lead times. Found at submittal review, it can mean a reorder. Found after installation, it means adding a run-around loop to units not built for one, plus more heating capacity. The GC priced it at $150,000 to $500,000 with 8 to 30 weeks of delay from AHU lead times. Fixed before construction, it was $2,000 to $5,000.

The fifth was bulk gas tanks too close to the building. The lab spec, in Division 22 and the lab gas sections, called for a bulk liquid nitrogen tank and a bulk CO2 tank outside the building, piped to the labs. The site plan on C-101 put both tanks on a pad next to the loading dock, convenient for delivery trucks.

Bulk cryogenic and compressed gas storage has required separation distances from building openings, air intakes, property lines, parking, and other hazards. The pad was within those distances of a dock door, an AHU intake on the low roof above, and the property line. The site plan also showed none of the bollards or the truck access path the gas supplier requires.

The fire marshal can refuse the installation, and the supplier will not fill a tank in a noncompliant location. Moving the pad after the site is built means new concrete, rerunning vacuum-jacketed piping, and site rework, late in the job when tenants are ready to move in. The GC priced it at $30,000 to $150,000 with 2 to 6 weeks of delay. Fixed before construction, it was $1,000 to $5,000.

See life science lab drawing review, New Jersey plan review requirements, laboratory construction drawing review, adaptive reuse drawing challenges, renovation versus new construction, spec analysis, and the Dallas lab review.

$730,000 to $3.2 Million in Field Rework Fixed for $23,000 to $80,000

Helonic caught the reinforcement mismatch before steel work started, while the fix was still a structural redesign.

Fixed before construction, the five came to $23,000 to $80,000. Found in the field, the GC priced the same five at $730,000 to $3.2 million.

The flood elevation finding carried the largest cost and could have stopped the permit. The reinforcement finding was the one with the hardest deadline, because every trade that follows steel makes it more expensive.

The reinforcement, the air handlers, and the gas pad were each drawn to an earlier layout or a different building type than the one being built. Across 1,000+ drawing packages Helonic has reviewed, about 8 in 10 had at least one coordination conflict between disciplines. See what Helonic found across 1,000+ drawing reviews.

Lab Floor Loads, New Jersey Flood Elevations, and Bulk Gas Separation Under NFPA 55

New Jersey permits buildings under the New Jersey Uniform Construction Code, which adopts the International Building Code statewide. Flood hazard areas also fall under the state's Flood Hazard Area Control Act rules, administered by the Department of Environmental Protection.

ASCE 7 sets office floors at 50 psf live load with a partition allowance. Lab floors are commonly designed for 100 to 125 psf, and vibration for imaging suites is checked separately, often with AISC Design Guide 11. A conversion has to check every bay that picks up lab equipment, against the current layout.

Flood-resistant construction under the IBC references ASCE 24, which requires building utilities and equipment to be elevated or protected. New Jersey's design flood elevation sits above the FEMA 100-year level, so equipment that clears FEMA's line can still be too low.

NFPA 45 prohibits recirculating air from laboratory hoods. Energy recovery on hood exhaust has to use a method that cannot carry exhaust air back into the supply, such as a run-around coil loop.

Bulk cryogenic and compressed gas systems follow NFPA 55 and the International Fire Code, adopted in New Jersey through the Uniform Fire Code. Both set minimum distances from building openings, air intakes, property lines, and parking.

“The lab planner moved the freezer banks and microscopy suite, but the structural reinforcement drawings still followed the old layout. Helonic caught it before we started steel work. On a conversion, reinforcing after the ceilings and ductwork are in is the most expensive way to do it.”

New Jersey Office-to-Lab Conversion Review: Questions and Answers