Maintaining Facilities Operation During Re-Roofing: Assessing Impact and Preventing Interruption of Continuous Operations During an Overhead Re-Roofing Project

Maintaining Facilities Operation During Re-Roofing: Assessing Impact and Preventing Interruption of Continuous Operations During an Overhead Re-Roofing Project

By Chuck Whary
introduction
I- 1HE NEED FOR PLANT RENOVATION AND CONSTRUCTION FREQUENTLY CONFLICTS WITH THE
L-] Fneed for continuous operation of manufacturing facilities. The need for close coordination of access, space require¬
ments, and containment of construction operations tnitbiii a facility is obvious and part of any project engineer’s
_ plan of execution. When the construction project is outside a facility, however, the potential for conflict is not so
obvious. In most cases, a re-roofing project does not represent a conflict with plant operations and traditionally requires
only cursory notification to prevent access problems and ensure utility availability. The following case history serves to
advise engineers and contractors of the potential for serious interference with certain manufacturing processes and the solu¬
tion employed in this specific case. This solution will be made part of our re-roofing process as required in the future.
Project Synopsis This project scope was to remove the existing roofing system
down to the steel decking. The replacement roof system con-
AMP Inc., East Berlin, PA, manufactures electronic terminals
and connectors for a wide variety of applications.
sisted of polyisocyanurate insulation, reinforced EPDM mem¬
brane, and the used existing river ballast, due to its excellent
Their overall building is 230′ x 310′ and was constructed in condition.
the early 1970s. The original roof construction consisted of the
following: steel decking over steel
joists, fiberglass insulation boards
placed on top of the decking, and a
ballasted EPDM membrane (riverwashed
stone ballast). The approxi¬
mate building usage allocations are:
65% light manufacturing, 20% plating,
10% office space, and 5% mainte¬
nance.
The structure maintains a positive
building pressure of approximately
+0.05 to +0. 10 inches (water column)
in all areas of the building except plat¬
ing. The plating area maintains a nega¬
tive pressure of approximately -0.05
inches. This is an AMP requirement to
prevent the expulsion of plating atmosphere and to ensure treat¬
ment of all associated vapors present as a by-product of the
plating process. These are the normal operating parameters for
the facility.
Manufacturing Process
Interference Identified
As the original roof was being
removed over the north end of the plat¬
ing area, airborne contaminants gener¬
ated by the tear off began to infiltrate
through the construction opening of an
exhaust fan. These contaminants had
the potential to enter and contaminate
the open plating baths, thus ruining
product and warranting a line shut
down. The roof was secured and work
was shifted away from the plating area
immediately until this issue was resolved
The plating line needed to remain in
operation 24 hours a day, 7 days a week to support manufactur¬
ing demand. The threat of contaminating the plating line using
the current methodology was high and presented an unaccept¬
able risk to the process If contamination of the plating opera-
February 1998 Interface • 27
Removal of all foreign materials from deck area.
tion took place, the cost estimates for replacement of the plat¬
ing line baths, potential lost manufacturing, generation of
excessive waste, and loss of wages were projected to be in the
low to mid six figure range. It was obvious that, before con¬
struction could continue, new safeguards had to be added to the
re-roofing process
Solution to Infiltration Problem
The approach first offered by the contractor was simply to
tent the plating line in its entirety to prevent any airborne con¬
taminants from infiltrating. The bid was $31,500 with a pro¬
jected delay to the schedule of three weeks. AMP Engineering
felt this cost was appropriate due to the complicated nature of
the plating area construction and the need for a variety of
accesses by the plating personnel to continue operation.
Surrounding areas within the designated plating area, however,
would not be protected and airborne contamination was still
likely to occur. This approach also would have, to some extent,
restricted access to the plating line for its operators. The addi¬
tional cost and schedule implications represented a significant
negative impact to the project.
After further evaluation by Jeff Paul, our HVAC engineer, and
myself, an alternate plan was developed With the use of the
building HVAC system, we would alter the building’s
positive/negative pressure relationships. This alteration, in con¬
junction with other measures to prevent large particle infiltra¬
tion at the source, would force contaminants to stay outside the
envelope and secure the entire plating area from infiltration.
The plan was to provide positive building pressure while the
demolition of the existing roof was accomplished Then, after
all foreign materials were removed and final sealing of the
remaining openings was accomplished, the building pressure
would be returned to a slight negative pressure to enable the
new insulation and membrane to be installed. The temporary
manipulation of the pressure was reviewed with the manufactur-
Sealing the deck seams with silicone caulk, and deck flutes with expandable
foam
ing process owners and compensations made to the process
exhaust system.
The following outline indicates the steps that were required
to accomplish the work over the plating lines:
1. Seal off all the roof openings possible from inside the plat¬
ing line area with the use of an expandable foaming agent. Add
secondary plastic containment under duct and pipe penetrations
which penetrate the roof. Cover all strategic items with plastic.
(This work was accomplished using a local general contractor.)
2. The HVAC system supporting the plating line operation
was changed for a short period of time to a positive pressure to
restrict any airborne contaminants from infiltrating the area. To
achieve this, building exhaust fans dedicated to the plating area
were turned off. The air handling unit which supplies air to the
plating area was changed from low winter to high summer set¬
tings. The main plating exhaust ventilation system was not
altered and remained in normal operation status. This changed
the pressure from negative to positive. (This work was accom¬
plished with AMP’s building maintenance person following the
guidelines set forth from Jeff Paul.)
3. After the removal of existing roofing materials from the
top of the roof, the area was cleaned of all remaining foreign
materials. This work was accomplished with the use of shop
vacuums. At that time any remaining roof openings that were
not accessible from inside the plating area were to be sealed
with an expandable foaming agent. (This work was accom¬
plished by the on-site roofing contractor.)
4. Finally, all the steel roof decking seams were caulked with
a silicone caulk (This work was accomplished by the on-site
roofing contractor.)
This approach provided a normal working environment for
the plating operators, and most of all, ensured the entire plating
area remained free of any airborne contaminants. The cost for
this work totaled $8,900 and added fewer than three days to
the schedule, considerably less than the projected $31,500 and
28 • Interface February 1998
three weeks projected for tenting.
After a meeting with all the parties affected, this approach
was adopted. A test area was established and monitored very
closely by both plating personnel and AMP Engineering.
Building pressure in the plating area was maintained at a posi¬
tive range of +0.07 to +0.14 inches for removal and returned
to a negative pressure of -0.06 to -0.10 inches. The test
proved to be successful and the remaining work proceeded as
planned.
Conclusion
The plating area re-roofing was accomplished in three work¬
ing days. There was no airborne contamination and no disrup¬
tion in operations. The benefits of the success of this approach
are twofold. First, a careful evaluation of special requirements of
manufacturing processes inside a facility will be conducted as
part of the planning process for all roofing projects in the
future. Second, in the event that special requirements are identi¬
fied, a tried and true methodology is available for implementa¬
tion to avoid contamination problems in the future.
Chuck Whary is a facilities engineer at AMP Incorporated, ‘
based in Harrisburg, PA. During his 32-year career, Chuck has
i worn many hats. He started out in the nuclear engineering field and
expanded into other fields of expertise. In 1987, Whary entered into
‘ the facilities arena and has remained there ever since Chuck is in
charge of roofing, parking lot, and cithl/structural projects at AMP.
Lain. Ill ■ .1 .. .. — . . . HI in . ri
Cold Weather Application Tips For Roof Coatings
A Roof Coatings Manufacturer’s Association (RCMA) TechNote
The viscosity of bitumen is temperature sensitive—thinner and
more fluid when hot,- thicker and more viscous when cold.
Today’s manufacturers of cold applied (liquid at room tempera¬
ture) asphalt roof coatings formulate their product to be usable at
ambient temperatures as low as 40 degrees Fahrenheit and up to a
high temperature of around 120 degrees F. Water-based coatings
and coal tar coatings are usually applied at 50 degrees F or higher.
In order to cover the wide temperature range, some manufactur¬
ers offer “all temperature” products, while others may offer winter
grade, summer grade or intermediate grade products. Check with
your supplier or manufacturer to determine which route to follow
to enable a proper product selection. If the manufacturer offers
various viscosity grades, find out how to distinguish one grade
from the other. Also, check how the containers are marked and
identified. Whatever the weather, there are always important “do’s
and don’ts” to follow for a successful system application.
Storage
Keep the product as close to room temperature as possible. A
heated warehouse is ideal. If kept outside, store the containers as
close together as possible under a tarp. This will slow down the
internal temperature drop of the product, keeping the viscosity
and application properties closer to standard for a longer period of
time. This is also important when using asphalt saturated roofing
felts in cold weather. These felts can become brittle when cold
and can crack at temperatures under 40 degree Fahrenheit.
Unsaturated membranes, such as polyester, are not affected by
cold temperatures (but must be kept dry).
Heating
With proper storage, heating should not be necessary. On the
jobsite, the use of heated storage cabinets/units for heavier-bodied
coatings, or warming devices which use circulating oil to heat liq¬
uid roofing materials for easier spray application, may be utilized.
Consult the equipment manufacturer for information on the safety
requirements pertaining to whichever heating device is used.
Surface Preparation
Never apply the product to a frost- or ice-covered surface. Once
the area is free of frost, ice and/or snow, follow the manufacturer’s
standard application directions. In addition to removing frost, ice
and/or snow, the surface must be dry for solvent-based coating
products unless using specially formulated wet surface products.
Slightly damp conditions may be acceptable for emulsions.
Application
If possible, wait until afternoon on a sunny day. This will enable
the roof to warm up as much as possible. Remember when work¬
ing with a black roof, the surface will absorb heat, making the roof
temperature warmer than the air temperature. This will accelerate
the overall cure rate. Special considerations may be required for
certain coatings, such as emulsified asphalt aluminums. Specific
instructions from the manufacturer should be followed.
Cure Time
While modern technology permits the application at low tem¬
perature, the cure time can be longer than on a warm summer day.
A product that may cure over night at a temperature of 70 to 75
degrees F may take several days to cure at 40 degrees F.
Remember that emulsion type coatings require temperature con¬
ditions which permit thorough evaporation of the water content
before the film is subjected to rainfall, freezing, or standing water
One can also consider use of a polymer-modified emulsion for use
in cooler temperatures as these products tend to have shorter set
and cure times.
In conclusion, select one of the many fine roof coating products
that have been formulated for use during cold weather. When in
doubt concerning the product or the particular weather condi¬
tions, give the manufacturer or supplier a call to discuss your par¬
ticular situation and product selection so that your cold weather
application or repair will yield the desired results.
February 1998 Interface • 29