Demonstration Project, Prescott Ontario
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
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.
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.
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:
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.
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.
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:
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:
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 Detection /Activation system components include:
In a FAST system installation, the pavement sensors should have the following characteristics:
The Pavement Sensor itself must:
Atmospheric sensors are to address the following:
In a FAST installation, the remote processing unit should:
The Fast Data Server:
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.
The Fast Hydraulic subsystems consist of:
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:
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
Total Preliminary Budget Cost: $239,000
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.
The system should be maintained in accordance with the Vendors suggested procedures.
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.
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.
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:
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:
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.
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:
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:
If problems in the system are identified, then MFPA will:
If work is required at the site, then MFPA:
A number of lessons were learned through the process of designing an installing the FAST system at the 416/401 interchange:
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:
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: