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Anti-Icing on
Structures Using Fixed Automated Spray Technology (FAST)
Demonstration
Project, Prescott Ontario

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Paper
Prepared for Presentation at the Partnering with Construction and Maintenance
Contractors to Achieve Environmental Protection Session of the 2001 Annual
Conference of the Transportation Association of Canada, Halifax, Nova
Scotia
May 1, 2001 |
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Overview
This paper overviews the selection, design, implementation and
performance of Canada's first fixed automated anti-icing spray system
installation for a highway/roadway application. Installed in the fall of 2000
on the northbound 416/401-interchange structure, the system has been in service
for the entire winter of 2000/2001.
The construction of this new bridge was completed in September
of 1999. During the first winter of operation a number of weather related
accidents occurred on the structure. For a number of years the Ministry of
Transportation, Ontario (MTO) has been investigating anti-icing and (Advanced)
Road Weather Information Systems ((A)RWIS) as independent approaches and
systems to complement the established levels of service for roads during winter
storms.
Based on its own research and the experience of other agencies,
MTO believed that there was an opportunity to significantly reduce the
potential for icing on the structure. This could be achieved by remotely
sensing potential frost and ice and automatically applying a liquid deicing
chemical before it actually formed. The FAST system continuously monitors
conditions on the structure and based on the detection of critical threshold
parameters it automatically sprays the chemical just in advance of icing
conditions. The structure in question is a 165m super-elevated, high speed,
freeway-to-freeway ramp with a design speed of 130km/hr and a 3000 AADT. Since
putting the system into service there have been no weather related
accidents.
The Ministry and its maintenance contractor have also taken this
opportunity to evaluate the performance of Liquid Potassium Acetate. This
chemical is not on Environment Canada's list of road deicing chemicals which
are under consideration to be designated as "toxic" under Section 64 of the
Canadian Environmental Protection Act, 1999 (CEPA 1999).
This report reviews the FAST installation at the site, the roles
of the partners in the implementation and operation; how a desire for enhanced
response time, increased safety, and reduced environmental impact, resulted in
study and implementation within a 6 month time period; project costs; approach
to study, design, procurement, contracting and risk sharing; lessons learned
during design and through the operation to date and other relevant points which
maybe of interest to road authorities. |
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Objective |
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For number of years the Ministry of Transportation, Ontario
(MTO) has been investigating Anti-Icing and (Advanced) Road Weather Information
Systems ((A)RWIS) as independent approaches and systems to maintain the
established levels of service for roads during winter storms and to improve
road safety.
MTO, based on their own research and the experience of other
road agencies, believed that there was an opportunity to significantly reduce
the potential for icing on the Highway 401/416 interchange northbound structure
(see figure 1). This could be achieved by remotely sensing potential frost and
ice using an ARWIS and automatically applying a liquid deicing chemical before
it actually formed. The Fixed Automated Spray Technology (FAST) system
continuously monitors conditions at the structure and based on the detection of
critical threshold parameters automatically fires, spraying the chemical just
in advance of icing conditions. The selected spray system was required to
effectively apply the liquid to the driving surface under a range of weather
conditions and depending, on how the programmable logic was configured,
continue to monitor conditions and automatically either repeatedly reapply the
anti-icing chemical if the chemical becomes diluted or, deactivating the
program in the event of a heavy snowfall. Deactivation is required since FAST
system was intended as an anti icing system, not a snow removal system.
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Process |
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During the first winter of operation, the northbound
416/401-interchange structure a number of weather related accidents occurred on
the structure. In reviewing the nature of the problem it became apparent that
there existed a combination of factors at the site which presented a challenge
for the maintainers and which made it worthy of note:
- The structure, although relatively new, had already developed
a history for accidents.
- The structure carried a volume of 3000 AADT and was a key
route to the Nations' Capital.
- The structure is a high-speed ramp on a rural freeway.
- The alignment of the structure and topography meant the
prevailing winds were at most times running across the deck.
- The location was remote from the dispatch location and not in
the same micro climactic zone.
- The structure was prone to icing earlier and more often than
the interconnecting segments.
MTO felt that the problem warranted a unique solution which
included automated detection and chemical application and began conversations
with a variety of agencies and vendors regarding the suitability of the
structure for installation of a FAST system.
Mark F. Pinet & Associates Limited (MFPA) an Eastern
Ontario consulting engineering firm with extensive Advanced Road Weather
Information System (ARWIS)/ Road Weather Information System (RWIS) experience
was retained by the Ministry of Transportation, Ontario (MTO) to complete a
feasibility study, Request for (vendor) Information (RFI) and Request for
(contractor) Proposal (RFP) relating to the purchase and implementation of a
FAST system at the site. Following the procurement approval, MFPA was retained
by Cruickshank Construction to complete the design, installation and
commissioning of the fully automated "Boschung" FAST System. . The system was
installed in September of 2000 and the commissioning of the final components
was completed on mid October 2000.
Cruickshank Construction has been employing the system to
service the structure during the winter of 2000/2001 and MTO has been supplying
the deicing chemical under the Area Maintenance Contract. Mark F. Pinet &
Associates Limited has been retained by the Ministry to provide support and
technical services relating to the on going service and performance monitoring
of the system through the winter to ensure that the system operates as
intended. As part of that assignment MFPA is also required to prepare this
summary report which describes the process and the system as installed.
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Description and
Design |
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Description Of The Location And Structure
Highway 401 through this section is a four lane rural freeway
constituting the main commercial truck and passenger route between Toronto and
Montreal. Highway 416 is also a four lane rural freeway carrying traffic to and
from Highway 401 and Ottawa. The junction of the two highways occurs near
Prescott between Cornwall and Brockville. The site has a micro-climate, which
is subject to "lake effect storms" from the St. Lawrence River which is in
close proximity and south of the site.
The structure is a 165 meter long, 11.2 m wide, super-elevated,
concrete, high speed, freeway-to-freeway ramp with a design speed of 130km/hr
and 3000 AADT on one single lane in the northbound direction. The structure
features a paved deck with a shoulder inside and outside of the 4.75 meter wide
through lane.
Description of Fixed Automated Spray Technology (FAST) System
Fixed Automated Spray Technology (FAST) involves the sensing of
pending frost and ice and the preemptive, automated spray application of liquid
anti-icing chemicals. The ministry's objective was to have the system's
technology accurately predict the road surface temperature and icing conditions
based on detection by the system and the system automatically spray the deicing
chemical, immediately in advance of icing conditions. In order to meet this
objective the FAST system would be made up of three subsystems:
- The RWIS Detection and Activation System
- The Hydraulic System, and
- The FAST System Server.
Through research by MFPA, it was determined that all the vendors
sell systems which are fixed and will spray the desired surfaces, however the
range of options to activate and the degree and accuracy of detection is
diverse. The level of sophistication also has a significant affect on the
overall cost of the system and installation. The range of automation options
available includes:
- Manual detection and activation on site using patrols
- Automated detection at the site, remotely alarmed and manual,
on site activation
- Automated detection at the site, remotely alarmed and manual,
remote activation
- Automated detection and activation at the site based on
programmable logic complete with continuous recording of data relating to
atmospheric and pavement conditions as well as system hydraulic operations
As a result of discussions with the Ministry staff it was agreed
that only the combination of last two options was acceptable to meet the
Ministry's objectives identified at the outset of the project notwithstanding
there was a significantly higher cost for the system purchase and
implementation.
In order to meet the detection and activation specifications the
vendors relied on demonstrated RWIS technology. During the implementation phase
it was agreed that providing the balance of the equipment required to make the
system a full RWIS station could further extend the benefit of the FAST system.
The incremental cost for this improvement was approximately 5% of the system
cost. With this change it will be possible to extrapolate the observed site
conditions to other similar locations, in the same micro climactic zone
following data assimilation and based on expert interpretation or modeling.
The Ministry has been investigating the use of a variety of
chemicals and chemical mixtures to maintain the prescribed level of service and
enhance safety for the motoring public in all weather conditions while reducing
the cost of application, reducing environmental impact and extending the
life-cycle of the infrastructure. The uncertainty over the type of deicing
chemical, or mixture of chemicals applied or carried onto the structure by
vehicles is a significant, but an inevitable problem. Despite this, it is
imperative that the detection system accurately predicts the freeze point of
the solution on the structure; otherwise it becomes a reactive deicing system
instead of a proactive anti-icing system. The consequence of inaccurately
predicting pending freezing conditions either means excessive and unwarranted
use of chemical or potentially increasing the driving hazard by making the
conditions worse than they otherwise would be by applying a deicing chemical
and then having it refreeze. To date only active pavement sensor technology,
which freezes a sample of the pavement surface (verses passive which measures
conductance) is able to accurately predict the freeze point of a chemical
mixture, of varying relative concentration. The incorporation of active sensors
has however introduced different technical issues from those encountered for
passive sensors as a result of the new requirement to power the pavement
sensor, which results in slightly higher costs for system purchase.
The ARWIS Detection and Activation System
The Detection /Activation system components include:
- Pavement sensors
- Meteorological (Atmospheric) Sensors and
- Remote Processing unit (RPU) to process the raw data and
react to it
Road Condition (Pavement) Sensors
In a FAST system installation, the pavement sensors should have
the following characteristics:
- Ability to measure or detect the following condition data:
- Pavement surface temperatures (measured)
- Subsurface temperature (measured)
- Moisture- dry, moist, or chemical wet (detect)
- Ice, snow, frost conditions (detect)
- Concentration of residual chemicals and /or anti-icing
agents (detect/ measure)
- Freeze point detection for each of the following
potential liquid deicing chemicals:
- Sodium Chloride (Salt)
- Calcium Chloride
- Magnesium Chloride
- Magnesium Acetate
- Potassium Acetate and
- Mixtures thereof.
- Demonstrate a high degree of sensitivity at the two important
temperature thresholds (freezing point with no deicing chemical present) and
the freeze point where the deicing chemical fails to be effective even at high
concentrations (approximately -20 degrees Celsius).
- The vendor was required to specify the number and location of
the sensors to ensure adequate and accurate detection of critical conditions
required to trigger the initial and subsequent anti-icing/deicing spray
applications.
The Pavement Sensor itself must:
- Have thermal conductance similar to the road surface
- Be either thermally passive (no heating or cooling) or
thermally active (artificially heating or cooling) as required to meet all of
the specifications above
- Be similar colour and have solar reflectivity characteristics
similar to the road surface;
- Have wear characteristics similar to the road surface
- Be supplied:
- With a sufficient length of cable and extension cable as
required.
- With Splice Kits and Sealants
- So as not to require penetration of the bridge deck/or
waterproofing membrane
Atmospheric Weather Sensors ( Full RWIS alternative)
Atmospheric sensors are to address the following:
- Air temperature;
- Wind speed and direction (measured);
- Precipitation (detection);
- Relative humidity (measured);
- Dew Point (calculated);
- Measure data at World Meteorological Organization (WMO)
regulation height;
- Must be either tolerant to salt or other chemicals or located
so as not to be adversely affected by the spray from vehicles.
Remote Processing, Data Logger Unit (RPU)
In a FAST installation, the remote processing unit should:
- Collect and store a minimum of 24 hours of data from the road
condition sensors and atmospheric weather sensors for transmission to the FAST
Data Server via Modem. Data is recorded against the real time for performance
review, at a later date;
- Trigger the spray system, based on observations from the
detection system;
- Select and initiate an appropriate spray program in response
to the specific observed condition;
- Temporally activate or disable the spray system according to
the operating logic, manually on site or remotely via dial up modem;
- Be designed based on an "Open System Architecture" to
facilitate integrating additional sensors (i.e., pavement condition,
meteorological, traffic counters, loop detectors, video cameras) and outputs
(e.g. message signs) to be added.
FAST Data Server
The Fast Data Server:
- Is the data warehouse and communication hub for the FAST
System;
- For security reasons, it is located offsite from the FAST
RPU;
- The system often is connected to the clients network in order
that the data can be backed up;
- The server dials out to the FAST site on a regular interval,
retrieves and archives the RPU atmospheric, pavement condition and FAST
hydraulic system data;
- The system users access the data from the server via dial up
or network connections and employ proprietary vendor software to view the data
in a graphical and tabular format;
- Allows the monitoring of the FAST system operation, system
administration, software upgrades, debugging and diagnostics remotely via
modem; and
- The server restricts user privileges as dictated by the
system administrator to allow users a full range of options from read only
privileges all the way up to remote operation of the system and remote
adjustment of system operating parameters.
Remote User Interface Software
The Vendors proprietary software can be used to view existing
conditions, archived data, and a 24-hour operating history. Depending on the
assigned user privileges it may be used to operate the system.
FAST Hydraulic System
The Fast Hydraulic subsystems consist of:
- Pump station;
- Nozzles;
- Hydraulic Piping and Control wiring;
- Valve Boxes.
Pump Station
A pump house was constructed at the site to enclose all the
required mechanical, power, communication and monitoring equipment required for
the proper functioning of the spray system. In addition to the structure, a
chain link security fence was provided to secure the installation.
Within the pump house the following components are found:
- Pump station
- Pump;
- Chemical reservoir;
- Control valves;
- Filters;
- Relays;
- Reservoir level sensors;
- Power supply equipment;
- Communications drops.
The vendor provided the complete pump station as a stand-alone
package consisting of pumps, valves, metering devices, connections, controls,
sensors, and storage tank. Separate panels for the electrical distribution and
the pump station controller are also located in the pump house.
The pump controls are located in the pump house and contain the
high power switches and relays, which switch the pump on and off and monitor
the relevant levels and pressures.
The system may be activated from a number of sources: remotely,
from a page; on site, manually (switch on the outside of the barrier wall at
the west side of the north abutment); or automatically, based on certain
atmospheric and /or pavement conditions which are observed by the ARWIS (AMS)
RPU station from the atmospheric and or pavement sensors.
Spray Nozzles
The Spray nozzles were originally specified as parapet style,
side mount nozzles so as to minimize the impact on the existing structure. It
was later determined that a flush mount nozzle embedded in the pavement would
require less damage to the structure. The obligation to provide and specify a
sufficient number of spray nozzles was transferred to the vendor to assure
adequate coverage of critical locations for initial and subsequent spray
applications. The nozzles were directionally adjustable in all three axes and
were installed in advance of the structure, at the direction of the vendor, to
ensure that the deicing chemical would be tracked onto the structure. The spray
nozzles specified are resistant to severe environmental conditions such as salt
and other chemicals. The materials and accessories provided by the vendor
consist of: nozzles, epoxy, sealant, mounting and adjustment hardware.
Mechanical Distribution Piping
The vendor was required to provide pipes, pressure fittings,
valves, reservoirs and control wirings and mounting brackets. These conduits,
fittings and accessories are resistant to severe corrosive environment
conditions such as salt and other deicing chemicals. The flexible piping
supplied by the vendor is manufactured specifically for the application. The
flexible plastic tubing makes it easier to work with for the installation;
ensures corrosion resistance and allows for a limited range of movement from
frost action, or as a result of accident impact. Stainless steel mechanical
connectors were easy to work with and resist corrosion.
Valves
Sufficient manual valves were installed to allow for partial
system operation in the event of accidental impact damage. Solenoid actuated
stainless steel valves allowing control of liquid to the spray nozzles
controlled valves between distribution piping and lateral branches were
employed.
FAST System Controller
The pump station controller is located in the pump house and
controls both pump and valve operation. The system will on a regular basis
perform a self-diagnostic test to confirm the system is ready to spray the
deicing chemical. In the event that the system detects a fault, it issues an
alarm at the pump house, which is relayed to the RWIS RPU and is picked up by
the server and identified as an alarm on the server and then to the user
terminal. In the event of an alarm it must be determined the nature of the
fault and the situation remedied before the FAST will spray automatically again
and depending on the nature of the fault (e.g. low chemical level or loss of
pressure) may not allow the system to fire at all. |
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Research and
Procurement |
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Literature relating to experiences with FAST systems was
reviewed from a variety of road winter maintenance organizations in the United
States. A list of potential vendors was developed and a number were requested
to provide technical literature and brochures outlining system principles,
specifications and features of their respective systems. A request for
information (RFI) was then prepared which outlined the general scope of work
and ensuring enough information was provided to have the vendors prepare a cost
estimate for supply of the system and the limited number of services they would
be required to perform. The research undertaken provided background for the
feasibility study, which was intended to identify the system vendors as well as
the available and currently employed systems. The report also drew conclusions
on which system Vendor, methodology and equipment was best suited for MTO's
specific requirements on the subject site, based on the best value for the cost
and estimated the cost of the complete system.
Once MTO selected the vendor, MFPA worked with the
implementation "Contracting Team" and vendor to develop the necessary
instructions, detailed design drawings and specifications; expedited review and
approval and then supervised and co-ordinated installation of the FAST system
by the Ministry's contractor(s) under the direction of the system vendor.
Details of the work plan were coordinated with the vendor, contractor and the
Ministry such that qualified knowledgeable staff and/or local contractors were
utilized to support and work with the vendor thereby ensuring that their system
was installed and operated as intended.
Procurement
Capital funding for the project was provided as part of the
rehabilitation of the northbound 416 lanes. The Ministry at the time had two
contracts underway, which had boundaries of their work, which covered the
subject site. These contracts were for the reconstruction of the northbound 416
and the Area Maintenance Contract (AMC). MFPA repackaged the RFI as a fixed
price request for proposal (RFP) and the Ministry administered the procurement
process with the two contractors. Cruickshank Construction was selected as the
successful proponent and proposed employing Boschung America as the Vendor. The
work was added as an extra to their existing AMC contract. |
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Risk Sharing, Partnerships with Industry,
MTO |
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The 416/401 FAST Project was completed in the spirit of a
demonstration project with all participants assuming some of the risk. MTO
needed to deal with a single contracting party, which was responsible for:
supplying the equipment and possessed the technical capability to ensue the
system would work as intended; could supply system maintenance and service
locally; and could meet the ministry high liability insurance requirements.
Since the project was a first in Canada, none of the
participants had worked with the Vendor or their systems prior to this project.
MFPA was the only participant with any experience with RWIS and sensor
installation on bridges. All participants however recognized the potential for
the equipment to be used in the future and as such were willing to share some
of the risk for the services or equipment for which each of them respectively
supplied in the undertaking. All participants supplied equipment and services
for which they were not fully compensated with a view of gaining experience and
insight into FAST and demonstrating the technology could work to meet the
ministry's objectives. |
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Installation |
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Design and Project Management
Despite the contracting parties being MTO and Cruickshank it was
understood that project manager held much of the responsibility to ensure that
the system would perform as anticipated since it was the common thread in the
implementation team from the feasibly phase to the commissioning phase. The
vendor provided a limited amount of generic engineering design based on
standard details. Details of the site, adaptation to the existing structure,
pump house, utility services, system architecture and configuration to suite
the local application were developed by MFPA. The actual ARWIS instrumentation
installation was completed by MFPA. The balance of the work related to the
installation of the complete and operational FAST system including all the
distribution piping and appurtenance installation was performed under the
supervision of the Project consulting engineer, Mark F. Pinet and Associates
Limited.
Installation by MTO's Contractor
Cruickshank Construction Limited was selected as the General
Contractor for the project and the work was performed as an extension to their
existing Area Maintenance Contract. They retained all other members of the
implementation team including consultants, contractors, and the vendor. In
addition to acting as General Contractor they were responsible for the
underground plant for the FAST, the civil works and the Pumphouse construction.
Cruickshank also retained a hydraulic contractor; Central Source Irrigation,
who possessed substantial experience with similar large scale automated
hydraulic systems to complete the mechanical portion of the work.
Installation by the Vendor
The installation works completed by the vendor included; all
hardware and software for the RPU; all work not specifically identified as
being supplied or installed by the MTO's Contractor; commissioning and burn in
testing of the system and all components; pressure testing of the hydraulic
system and all components and training. |
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Budget Estimate and
Costs |
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Boschung America was the preferred vendor based on the value of
the performance of the system they proposed for the price. The following
outlines the estimated cost for a complete system provided and fully installed
at the subject site based on a conceptual design and Boschung as the vendor.
The following shows the components for a complete supply and installation of a
FAST system.
Original
- Equipment Supply (excl full RWIS)
- Installation*
- Civil
- Spray System
- Gantry System
- Electrical
- Engineering
- Contingency
Total Preliminary Budget Cost: $239,000
Additional Costs
- Upgrade to full ARWIS
- Security fencing
- Chemical supply
- Utility service extensions
- Maintenance
- Changes in Duty and Exchange
- Additional Research
Total Final Cost: $300,000
*The original budget was based on MTO retaining all the
subcontractors directly without a General Contractor.
The actual construction cost was $300,000. The Fast system
coverage is 1784.5 m2 on the bridge and 190 m2 on the approach to the bridge
for a total of 1963 m2 or $153/m2. Since this is a demonstration project,
future costs are expected to be higher. The annual operating cost is
approximately $15,000, or $7.64/m2 annually excluding annual maintenance of the
spray system, pumps and systems. |
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Maintenance |
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The system should be maintained in accordance with the Vendors
suggested procedures.
Start Up (Fall) In the fall the system should be
checked and refilled with chemical and the ARWIS station serviced. The entire
system should be checked for damage and repaired including replacement of any
failed joint sealant etc on the structure.
Shut Down (Spring) In the spring the system must be
flushed with clear water and the filters checked/replaced. The system is left
pressurized and any change in pressure is flagged as an alarm to the System
Administrator. The system should on a regular basis be cycled through using
clear water.
In addition, the following recommendations should be taken into
account.
- Follow the Vendor's operating manual instructions.
- The contractor will be required to monitor the chemical
levels within the pump house and refill the tanks to suit the intensity of the
storm.
- The contractor should employ good house keeping practices to
ensure the electronics are not damaged by humidity or the presence of the
chemicals.
- The contractor should adhere to appropriated health and
safety regulations and should have all WHMIS sheets and personal protective
equipment at the site for handling chemicals and any necessary safety equipment
within the pump house.
- Wiring is a combination of North American and European
voltages (120/208/230 volts) and must be fully inspected by the appropriate
electrical inspection authority. The maintenance contractor should use caution
when working around electrical equipment and appropriate warning signs shall be
used.
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Operational
Plan |
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In order to successfully integrate FAST into the Winter
Maintenance Service Provider's toolbox, a plan of operation must be developed
to fully integrate the new technology into all the related and affected
business processes.
The FAST system was to be operated as outlined in the operating
manual supplied by Boschung, the system vendor and as outlined in the user,
operator and maintenance training sessions provided by the vendor however it
was the responsibility, of the owner, in this case the MTO to:
- Obtain procedural approvals;
- Cause an adjust in maintenance operations under the Area
Maintenance Contract;
- Provide training, access and support to gain the confidence
of staff in the system;
- Provide access to the FAST system data to those inside and
outside MTO requiring it;
- Provide the necessary resources to monitor the performance of
the system to ensure that the system is operating as MTO intended i.e. that the
system was applying chemical at the appropriate time;
- Provide and understand the logic and timing for the
application of the selected anti-icing/deicing liquid chemical;
- Provide the necessary resources to monitor the system
operation to ensure that the system is continuously operating in the ready mode
and no system alarms have occurred during the self diagnostics testing;
- Select the and appropriate liquid chemical;
- Provide any warning signs to motorists to alert them of the
automated anti-icing /deicing operation;
- Pay the operating cost which include, power,
telecommunications, and supply of chemicals;
- Indemnify the General Contractor and Subcontractors against
future claims except for negligence specifically relating to the installation
of the FAST System;
- Ensure the RPU and pump house site is secure from
vandalism.
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System
Interfacing |
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The Vendor's user interface software provides a graphical
presentation to the operator, allowing them to control, manage, or observe, the
FAST system depending on the users authorized privileges. At the highest level,
only Administrators are permitted to modify FAST system critical threshold
operating parameters. As an example for an optimal effectiveness of the FAST
System, the Administrator is required to enter into the control mode and
customize the system set up to take into account various factors of influence,
including:
- The density of the traffic
- The selected sites for the installation of the meteorological
and road sensors
- The local climatic variations
- The choice of the spraying parameters.
After appropriate training is given by the Vendor, and under the
direction of the Owner, the Administrator is able to modify and enter
parameters. The vendor advises however that they will not be held responsible
for the consequences of hazardous, incomplete or lack of customization of the
system.
At the lowest level, a user would be permitted to only to view
current and historical pavement, atmospheric and system operating data, but
could not affect the operation of the FAST system using the interface software.
Software development is underway which provides these services over the
Internet to authorized users using a common Web Browser. |
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Monitoring |
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Notwithstanding the best efforts under the FAST installation
contract, the system provides the best available technology at the time but it
cannot however, be assumed to replace the requirement for regular patrols and
manual monitoring of pavement and forecasts of atmospheric and pavement
conditions.
This system is only a decision support system and is intended to
assist the road maintainer in making informed decisions about road maintenance.
It provides additional information allowing for proactive approaches to winter
maintenance. MTO should be continually monitoring the performance of the system
to ensure that the system is operating as intended and is applying deicing
chemical at the appropriate time.
The system, on its own, on a regular basis, performs a
self-diagnostic test to confirm it is ready to fire. In the event that the
system detects a fault, it issues an alarm at the pump house, which is relayed
to the RWIS RPU and is picked up by the server and identified as an alarm on
the user interface. In the event of an alarm the nature of the fault must be
determined by the system operator and the situation remedied before the FAST
will fire automatically again. Depending on the nature of the fault (e.g. low
level or loss of pressure) may not allow the system to fire at all. The FAST
has been installed and employs the default settings provided by the vendor,
based on dialogue with the MTO staff. The system will fire based on its
response to a number of environmental, atmospheric and pavement condition
parameters and is typically running in automated mode. It is difficult to
confirm pavement conditions without relying solely on the system log to the
conditions. As such currently, MTO relies on the Patrol Supervisor to verify
system operations. It has been suggested that video monitoring be performed so
that the timing and conditions for chemical application can be visually
confirmed as well as the response of the vehicles to the conditions and deicing
chemical application.
MTO retained MFPA to provide the monitoring services based on a
daily review of the system operation weekdays -Monday to Friday. Operational
reviews are done during and after a winter event and a monthly review and
summary report is prepared for submission to MTO; The monitoring relationship
is based on the following understanding of the relative responsibilities:
- The FAST system employs a number of preset but customizable
routines to respond to various alarms the system will generate. The appropriate
response to the alarm and therefore the routine is also dependant on the
deicing chemical employed since each chemical has a different freeze point,
tracking, hygroscopic properties and results in a different coefficient of
friction Boschung provided the logic and timing parameters for the application
of the selected anti-icing/deicing liquid chemical based on input from MTO.
- MFPA as system administrator, on behalf of MTO provided the
necessary resources to monitor the system operation to ensure that the system
is continuously operating in the ready mode and no system alarms have occurred
during the self diagnostics testing.
- The FAST system employs a number of internal and external
subsystems and components, which operate in an extremely harsh environment.
Communications, and power are provided to the remote location via overhead
lines. Each of these components is essential to the operation of the system.
Robustness of the entire system and the continued access of data into the road
maintainer is the aim of the system administrator. The System Administrator is
responsible for the electronics, but also, communications, software and
hydraulic systems. Proactive regular monitoring of the all components of the
system to ensure the system is continuously in the ready mode is essential.
Reliability is essential to development of confidence in the system by the
Roadway Maintainers. In the event of trouble the System Administrator must have
available:
- The knowledge to troubleshoot the problems remotely
- Identify the problem and isolate the source
- Review standard troubleshooting list
- Refer to manufacturer
- Identify the remedial/corrective measures
- Undertake the corrective measures
- Remotely
- By System Administrator
- By the vendor and manufacturer's
representative
- On site
- The knowledge to troubleshoot the problems on site
- Identify the problem
- Review standard troubleshooting list
- Manufacturer Support line
- Identify the remedial/corrective measures
- Undertake the corrective measures
- Remotely
- By System Administrator
- By Manufacturer Support rep
- On site
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Service |
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MFPA conducts daily system and operational reviews. In the even
that the FAST displays a system related alarm, the problem scope is identified
and if required, the second part of the monitoring and service contract comes
into affect. The following service work is also being performed by MFPA:
Remote Service
If problems in the system are identified, then MFPA will:
- Co-ordinates service personnel and dispatched staff to affect
repairs
- Identify and co-ordinate warranty service
- Recommend appropriate repair methodology
- Isolate problems or if necessary refers them to the system
designer (Boschung) when required for advice and remote system repairs
- Advise the MTO of all activities through the Contract
Administrator
On Site Services
If work is required at the site, then MFPA:
- Provides field supervision of all warranty and non- warranty
repairs
- Undertakes repairs, if possible, at the approval of the
Contract Administrator
- Under the Maintenance portion attends the site on two
occasions, in the spring and fall, for site inspection and general maintenance
system review i.e. filters, pumps, RWIS components and the same and affect any
required maintenance.
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Lessons
Learned |
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Design and Installation
A number of lessons were learned through the process of
designing an installing the FAST system at the 416/401 interchange:
- Feasibility studies are necessary to identify and address
technical design and systems issues; structural and aesthetic concerns; costs
and warrants for the installation of a FAST system. The rationale for
installing a FAST system should be based on a benefit/cost analysis, which
takes into account the accident statistics for the site.
- Study, design and project management fees are in line with
other Information Technology (IT) systems integration assignments involving
hardware and software deployment, but may be greater than those for traditional
roadway infrastructure.
- It is important that local engineering, project management,
and coordination services are available throughout the design and
implementation process to deal with existing local regulations, conditions,
site topography, vegetation, utility services and on site installation details
which cannot be provided effectively by a vendor who may be located out of
province or country.
- Appropriate coordination for utilities and an allowance for
lead time, and cost when extending services to a remote site, is required.
- Shipment of materials from out of the country and overseas
presents some unique challenges. Materials manufactured and supplied though
NAFTA are not subject to duties. Changes in the exchange rate can occur between
the time budgets are prepared and when final costs are incurred.
- Vendor bill of materials and shipping documents should be
carefully reviewed and confirmed prior to shipment. Components not provided by
the vendor must be identified and sourced. Sufficient accommodation must be
made for delivery of unique components from a time perspective.
- Complete detailed installation manuals are required from the
Vendor during design;
- Wiring from European vendors must be fully inspected by the
appropriate electrical inspection authority. Personnel servicing the electrical
equipment must be aware and provided with adequate instruction from the vendor.
- Licences for proprietary user interface software must be
flexible enough to allow for access by the full range and number of interested
parties. Internet Browser enabled access using secure passwords is the
preferred mode. Both dial up and WAN access must be available.
- System data server must allow for full access to atmospheric,
pavement and FAST data to allow for data mining by the system administrator(s).
- The Vendor should make a full description of the FAST system
decision logic, programs and default variables available to the Owner.
Operations
It was expected that adjustments in "operations" would be
required as a result of implementing FAST. Operational adjustments would take
place on two fronts: physical operation of the FAST system, and in business
processes for the contractor and owner's winter maintenance activities.
A number of changes have been made in the system and team
operations, which include the following:
- Sufficient storage reservoir for chemical must be
provided on site. Originally the vendor had indicated that the reservoir tank
should have sufficient chemical capacity to last most of the season, however
early in the monitoring season it became apparent that his would not be the
case. The system regularly reported alarms for low chemical levels in the
reservoir. The maintenance contractor modified operations in that he would on a
weekly basis top up the pump station reservoir on site and ensure the on site
storage tank was refilled. After an intense event such as a freezing rain
storm, the levels would be checked, and during the fall, despite there not
having been precipitation, chemical levels may be down as a result of firings
to address early morning frost.
- The upper edge of super elevated bridges should be
cleared of snow. During the early part of the operating season it was
observed on site that the plowing operations left some residual snow and ice on
the upper shoulder (east side of the structure) and that on sunny days it
melted and ran across the structure. The pavement sensors detected the moisture
and since the air temperature was below freezing triggered firing of the
system. The snow and ice was removed on a regular basis and no further
unexpected sprays were recorded. Icicles were observed on the structure during
one early winter event however the phenomenon was not observed again and was
therefore attributed to a unique weather phenomenon.
- Early Warning for Maintenance Contractor. Part of the
attraction for implementing the system from the Maintenance contractor's
perspective was that the information derived from the 416/401 FAST could be
extrapolated to other similar structures within a reasonable distance from the
site so long as they were in a similar microclimatic region. The teams vision
was that the server would be located at the MTO district office in Ottawa which
is staffed twenty-four hours a day, seven days a week by ministry staff. When
the system would generate an alarm of pending ice, the dispatcher could then
alert other ministry staff and the contractor that other similar sites would
likely require attention. In doing this, the contractor would develop a system,
which would allow them to extrapolate the known conditions at the 416/401 to
other sites based on their expert knowledge of the relative local conditions at
other points/structures of concern. However to realize the entire benefit of
the expert system, more effort is required on behalf of MTO to ensure dispatch
staff are trained to read the system user interface and respond appropriately
to the alarms generated from the system.
- Adjustment of operating parameters versus successful
reduction in accident statistics. The Monthly Report Process afforded the
opportunity to review and potentially adjust vendor suggested default
parameters so as to optimize the use of deicing chemical and customize it for
agency or local preferences. As an example, it was found that the system did
indeed deactivated one particular program in the event of a heavy snowfall,
however it continued to fire using another program once it's threshold
parameters had been met. The rationale for implementing the FAST system was to
determine if this technology could reduce the number of weather related
accidents. The installation has been a complete success effectively eliminating
accidents during a severe winter season. The cost of chemical supply however
was in the order of $12, 000 verses an original estimate of $5000-7000. For the
peace of mind, the increase is a minimal cost and in point of fact the capital
cost of the entire installation may have been offset in the first year of
operation when compared to the cost of the incidents from the previous year.
The system vendor has only provided a limited amount of documentation on the
system decision logic and rationale behind the parameter settings citing
decades of experience in the field and unwillingness to disclose proprietary
intellectual property. It is of questionable value to expend a significant
amount of effort to reverse engineer the logic and then assess the data for
what would amount to a limited relative benefit in savings of chemical.
- The extent of people requesting access to the system
using the vendor's proprietary user interface software has far outreached the
number initially anticipated. The Vendor has only allowed a limited number of
licenses, which is insufficient to address the large number of team members and
staff who would like to view the relevant pavement, atmospheric and system
information. The system administrator has worked with Environment Canada who is
developing an interface, which will allow permitted users to the view relevant
FAST system information using their internet browser.
- It takes time to achieve "buy in" from both the
owner's staff and the maintenance contractor. The contractor must be motivated
to embrace the technology via either the carrot or stick. Full integration into
business processes will not occur the first season, but only as confidence in
the system is developed. Training, suitable to address a variety of levels of
expertise, will be required on an on going basis as a result.
- Potassium Acetate has proven to be an excellent
deicing chemical for this limited area. Significant tracking of the chemical
has been observed after the structure and the residual adheres well to the
driving surface once it dries.
- Aside from daily monitoring of the system, raw atmospheric,
pavement and system operational data was retrieved regularly from server and a
Monthly Summary Report was produced which overviewed the operation of
the system during the period. The purpose of the review was to analyze the data
and determine if the system variables could be modified to improve the
performance. The requirement for monthly reporting forced a regular
introspective review of activities by the FAST operations team: the owner, the
maintainer and the system administrator.
- The original intent was to have Video Monitoring
available on site to assist in system performance appraisals aid in the
assessment; however, the video monitoring was not available for the winter of
2000/2001. The system administrator as author of the monthly report therefore
had to rely more heavily on data mining, data analysis, daily monitoring and
field observation by the maintainer as a source of information.
- Access to the FAST server was required on a number of
occasions during non business hours to reset modems, which were preventing
access to system data by dial up clients. The system was configured to allow
dial up access through either the Ministry's WAN/LAN or via dial up connection.
The WAN/LAN connection which was the primary access for the Ministry was the
most reliable, however, access by the contractor, system administrator/monitor
and system vendor, was interrupted on a number of occasions since the modems
locked as a result of phone line or power interruption. A redundant server was
set up by Environment Canada to retrieve data directly from the site. The
Environment Canada server provided an alternative source of data for the team
members relying on dial up connections at those times.
- The vendor's user interface software proved to be
compatible only with Windows 98 for dial up, NT and 2000 for LAN and
many of the Ministry's PC's were still using Windows 95 and 98 which impeded
user interface installation.
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Reduced Environmental
Impacts |
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Environment Canada is reviewing whether road salts are hazardous
to the environment and have proposed the following with respect to an amendment
to the Environmental Protection Act:
"Based on the available data, it is considered that road salts
are entering the environment in a quantity or concentration or under conditions
that have or may have an immediate or long-term harmful effect on the
environment or its biological diversity and that constitute or may constitute a
danger to the environment on which life depends. Therefore, it is proposed that
road salts be considered "toxic" under Section 64 of the Canadian
Environmental Protection Act, 1999 (CEPA 1999)."
Potassium Acetate, as the deicing chemical, is not on the
proposed list.
Other relevant advantages of the use of FAST system technology
include:
- Application of deicing chemicals just in time, immediately
in advance of a critical event maximizes safety but reduces the amount of
chemical lost from the traffic passing, and as well avoiding application of
chemical when an event does not materialize.
- Minimizes the quantity of chemical applied by ensuring it is
effectively applied, uniformly, as a mist and takes advantage of vehicle
tracking to the greatest extent possible.
- Just in time application of deicing chemical in advance of a
critical event in an anti-icing application has proven to be effective in
breaking the pavement to ice bond and substantially reduces the effort (labour
and material) required for snow and ice removal.
- Potassium Acetate does not attack steel and concrete and
hence the use of FAST may extend structure life and potentially reduce future
rehabilitation costs. Tracking of salt from the previous section of highway is
a concern so the Fast system also covers the approach to the structure.
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Conclusions |
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- The lessons learned from the previous section may be of
interest to other road authorities considering a similar system.
- The Ministry is very pleased with the FAST installation in
terms of its success since weather related accidents have not occurred since it
has been in operation.
- MTO will in the upcoming year require the contractor to
interrupt application of deicing salts across the structure now that the
results respecting the safety of the structure have been achieved and
functioning of the FAST system has been confirmed.
- The Ministry currently reviewing additional applications at
locations where it appears FAST may be warranted.
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Document prepared by:
- Mark Pinet, Mark F. Pinet & Associated Limited
- Todd Comfort, Ministry of Transportation Ontario
- Michael Griff, Ministry of Transportation Ontario
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