U.S. Department of Transportation Federal Aviation Administration Advisory Circular

REFORMATTED FOR STYLE

Subject: AIRPORT SNOW AND ICE CONTROL

EQUIPMENT

Date: 6/30/92 Initiated by: AAS-120 AC No: 150/5220-20 Change:

1. PURPOSE. This advisory circular (AC) provides guidance to assist airport operators in the procurement of snow and ice control equipment for airport use.

2. CANCELLATION. This advisory circular cancels AC 150/5220-11, Airport Snowblower Specification Guide dated 4/10/78.

3. VEHICLE MOVEMENT

COORDINATION. Vehicle movements on airport operational areas shall be conducted in accordance with FAR Part 139.329 and appropriate provisions of AC 150/5200-30A, Airport Winter Safety and Operations.

4. APPLICATION. The Federal Aviation Administration (FAA) recommends the use of the guidance contained in this publication for procurement of snow and ice control equipment at civil airports. For airport projects receiving Federal grant-in-aid assistance, the use of these standards is mandatory and equipment procurement must be made through the competitive bidding process.

for

LEONARD E. MUDD

Director, Office of Airport Safety and Standards.�

6/30/92 AC 150/5220-20

iii

TABLE OF CONTENTS

Paragraph Page

CHAPTER 1. OVERVIEW.

1. Background

2. Classification

3. Content

4. Friction Testing Equipment

5. Use of Specifications

6. Variable Use of Equipment

7. Certification

8. Metric Units

9. Reserved

CHAPTER 2. ROTARY PLOWS.

10. Description

11. Snow Removal Requirement

12. Rotary Plow Capacities

13. Rotary Plow Selection

14. Supporting Carrier Vehicle 15-16. Reserved

CHAPTER 3. DISPLACEMENT PLOW.

17. Description

18. Plow Uses

19. Moldboards

20. Snow Deflector Shield

21. Cutting Edges

22. Plow Shoes and casters

23. Displacement Plow/Rotary Plow Relationship

24. Displacement Plow Selection 25-26. Reserved

CHAPTER 4. MATERIAL SPREADERS.

27. Description

28. Types of Spreaders

29. Dry Spreader Selection

30. Liquid Spreader Selection

31. Design and Component Layout 32-33. Reserved

CHAPTER 5. CARRIER VEHICLES.

34. Description 35-36. Reserved

CHAPTER 6 SELECTION OF ROTARY AND SNOW PLOWS.

37. Description

38. Minimum Equipment Requirements

39. Displacement Plow/Vehicle Compatibility

40. Selecting a Rotary Plow for Commercial and non-Commercial Service Airports

41. Selecting a Displacement Plow Blade Length 42-43. Reserved...........................................................................................................................................32�

AC 150/5220-20 6/30/92

iv

TABLE OF CONTENTS (CONTINUED)

Paragraph Page

CHAPTER 7. OPERATIONAL STANDARDS AND TESTING.

44. General

45. Additional Tests

46. Carrier Vehicle Tests

47. Rotary Plow Tests

48. Displacement Plow Capacity Test

49. Spreader Test

TABLES

Table 2-1. Rotary Plow Capacities Table 4-1. Spreader Capacity Chart

FIGURES

Figure 2-1 Single-stage Rotary Plow Figure 2-2 Two-stage Rotary Plow Figure 2-3 Typical Rotary Plow Types Figure 2-4 Rotary Plow Calculations for Airports without Commercial Service Figure 2-5 Rotary Plow Calculations for Airports with Commercial Service Figure 2-6 GVW and Horsepower Rating for Rotary Plows Figure 3-1 Functional Elements of Displacement Plows Figure 3-2 Carrier Vehicle Power versus Moldboard Length Figure 3-3 Effective Displacement Plow Blade Length Related to Snow Displacement Figure 3-4 Effective versus Actual Displacement Plow Length Figure 3-5 Displacement Plow Components Figure 3-6 Snow Displacement (tons/hr.) Related to Surface Area Figure 4-1 Dry Material Spreader Types Figure 4-2 Hopper Capacity—Sand Figure 4-3 Hopper Capacity—Urea Figure 4-4 Hopper Capacity—CMA Figure 4-5 General Design and Component Layout of a Dry Hopper Spreader

APPENDICES

Appendix 1 Specification for Carrier Vehicle (11 pages) Appendix 2 Optional/Alternate Equipment (4 pages) Appendix 3 Rotary Plow Specifications (3 pages) Appendix 4 Displacement Plow Specifications (7 pages) Appendix 5 Material Spreader Specification (4 pages)�

6/30/92 AC 150/5220-20

1 (and 2)

CHAPTER 1. OVERVIEW.

1. BACKGROUND. Runways and taxiways should be maintained, if possible, to a "no worse than wet" condition during inclement weather. To meet this challenge, the purchase of snow and ice control equipment will not only require significant financial commitments, but also careful planning.

Selection of equipment is based to a large extent on manufacturer's specifications. This Advisory Circular (AC) is designed to facilitate the purchase of equipment that is acceptable to the Federal Aviation Administration (FAA) for use on airports.

2. CLASSIFICATION. Snow and ice control equipment is generally classified by category based on the specific task that the equipment was designed to perform. This AC discusses several of these categories, e.g. rotary and displacement plows, material spreaders, and carrier vehicles.

3. CONTENT. Chapters 1-7 describe this equipment and present methods of selecting and testing that will meet sponsor needs and ensure compliance with manufacturer's claims. The remaining portion of the AC deals with equipment specifications. For example, appendix 1 contains specifications for a generic carrier vehicle while appendix 2 lists equipment options available for carrier vehicles, rotary plows, displacement plows, and material spreaders. Appendices 3, 4, and 5 cover specifications for rotary plows, displacement plows, and dry and liquid spreaders.

4. FRICTION TESTING EQUIPMENT.

Specifications for friction testing equipment used to conduct runway friction surveys during winter operations are found in AC 150/5200-30A, Airport Winter Safety and Operations and AC 150/5320- 12B, Measurement, Construction, and Maintenance of Skid-Resistant Airport Pavement Surfaces.

5. USE OF SPECIFICATIONS. These specifications can be used individually or in combination with one another. For example, an airport operator desires to acquire a new selfpropelled rotary plow. This unit consists of a carrier vehicle and a rotary plow head assembly. The operator would combine information in Appendix 1 with Appendix 3 and, if necessary, appropriate parts of Appendix 2 for the required specification. On the other hand, if only a rotary plow head assembly were required, Appendix 3 is all that is needed.

6. VARIABLE USE OF EQUIPMENT.

Depending upon conditions, a displacement plow supported by a sweeper may be all that is required to keep an airport open to traffic. At other airports, more diverse equipment may be needed. In assessing airport needs, the airport operator must compare the cost/benefit relationship of acquiring a multifunctional piece of equipment offering a number of attachments versus the acquisition of a single unit designed primarily to accomplish one task.

7. CERTIFICATION. Purchasers of equipment described in this AC should obtain a certification in writing from the vendor that the components constituting the whole of the equipment being supplied comply with the applicable performance, design or construction requirements of this specification. This certification is required if the equipment is purchased with Federal funds. In this event, a signed copy of the certification shall be made part of the equipment documentation.

8. METRIC UNITS. In order to promote an orderly transition to metric (SI) units, this AC contains both English and metric dimensions. The metric conversions may not be exact and pending an official changeover to this system, the English system governs.

9. RESERVED�

6/30/92 AC 150/5220-20

CHAPTER 2. ROTARY PLOWS.

10. DESCRIPTION. Rotary plows, also called "rotaries" or "snowblowers," are primarily used to cast heavy concentrations of snow away from airport operational areas such as runways and taxiways.

The equipment, which may be self-propelled or attached to a carrier vehicle, uses either one or more rotating elements (single or two-stage units) to disaggregate a snowpack. The disaggregated snow is then broken into particles small enough to pass through a casting mechanism and directional chute.

Because of their large capacity, self-propelled rotary plows are frequently required at medium to large airports while rotary plows attached to a carrier vehicle may be more appropriate at smaller facilities or facilities where the climate is less severe.

a. Single-Stage Rotary Plows. Single-stage rotary plows use one rotating device to accomplish both the disaggregating and the casting functions.

Single-stage rotaries may be of any suitable design with either single or dual turbine fans and with or without moveable or fixed side extension wings.

Two common designs are the scoop wheel type (figure 2-1), which may have a propeller-like precutter bar to break up hard snow, and the drum with turbine impeller type (figure 2-3g).

b. Two-Stage Rotary Plows. Two-stage rotary plows separate the snow gathering or disaggregating function from the casting function (figures 2-2 and 2-3). Disaggregators can be of any suitable design, such as a solid auger (single or dual) or ribbon reel (helical). Impellers, which cast the snow, can be of web or disk design.

c. Options. In selecting a rotary plow design (single or two stage) to meet the demands of local conditions, an airport operator should consider the various equipment options available to ensure that only the most effective unit is acquired.

11. SNOW REMOVAL REQUIREMENT.

Snow removal requirements are based on the annual operations at an airport and the amount of surface area to be cleared. These variables are described in AC 150/5200-30A, Airport Winter Safety and Operations, and must be determined as the first step in rotary plow selection. In areas of heavy snow concentration, the rotary plow is selected first because it dictates the selection of support equipment. Figures 2-4 and 2-5 reflect an acceptable method of rotary plow selection.

12. ROTARY PLOW CAPACITIES. Capacities for various rotary plow classes are shown in Table 2- 1 and may be acquired in either single or two-stage design. Their capacities are in tons/hour and the casting distance shall be measured from the longitudinal centerline of the snow removal unit to the center of mass within the perimeter of the cast pattern. The test shall be conducted when there is no wind.

13. ROTARY PLOW SELECTION. Guidance on the selection of rotary plows may be found in Chapter 6.

14. SUPPORTING CARRIER VEHICLE.

Carrier vehicles on which rotary plows are mounted should conform to the specifications in appendix 1 and to the plow manufacturer's recommendations for axle loading, operator visibility, and power train.

For vehicle controllability and safety, all-wheel drive shall be standard. Figure 2-6, GVW and Horsepower rating for Rotary Plows, shows the weight/horsepower (H.P.)/ snow capacity relationship between rotary plow classes.�

AC 150/5220-20 6/30/92

Table 2-1. Rotary Plow Capacities.

Casting Distance (1) Plow Size Class Feet Meters Minimum Capacity Tons/h (2) Small I 50 15.2 Up to 600 Medium II 75 22.9 1500 Intermediate III 100 30.5 2500 Large IV 100 30.5 3000 Very Large V 100 30.5 4000 150 45.8 3000 Extra Large VI 100 30.5 5000 and >

(1) As measured in paragraph 12. Rotary Plow Capacities.

(2) As measured in paragraph 47. Rotary Plow Test.

15-16. RESERVED.�

6/30/92 AC 150/5220-20

Figure 2-1. Single-stage Rotary Plow.

Figure 2-2. Two-stage Rotary Plow.�

AC 150/5220-20 6/30/92

Figure 2-3. Typical Rotary Plow Types.�

6/30/92 AC 150/5220-20

Figure 2-4. Rotary Plow Calculations for Airports Without Commercial Service.

ROTARY PLOW SELECTION CHART�

AC 150/5220-20 6/30/92

Figure 2-5. Rotary Plow Calculations for Airports With Commercial Service.

ROTARY PLOW SELECTION CHART�

6/30/92 AC 150/5220-20

9 (and 10) BLOWNEoPtRer :oE pNHuGolsrIisNoenEp Figure 2-6. GVW and Horsepower Rating for Rotary Plows.�

6/30/92 AC 150/5220-20

CHAPTER 3. DISPLACEMENT PLOWS.

17. DESCRIPTION. Displacement plows consist of a cutting edge to shear snow from the pavement and a moldboard to lift and cast the dislodged snow to the side of the cleared path. The cutting edge may ride in contact with the pavement or be held a small distance above it by means of shoes or caster wheels. A complete displacement plow unit consists of a plow, carrier vehicle, and accessories (see figure 3-1). Plow sizes may be classified as follows:

a. Small Plow. This category includes plows with cutting edge lengths ranging from approximately 6 feet up to 10 feet (1.8 m up to

3.0 m). Included in this category are underbody-mounted truck scrapers with similar length cutting edges.

b. Intermediate Plow. This category includes plows with cutting edge lengths ranging from approximately 10 feet up to 15 feet (3.0 m - 4.6 m). Underbody-mounted truck scrapers with similar length cutting edges are also included in this category.

c. Large Plow. This category includes plows with cutting edge lengths ranging from approximately 15 feet up to 22 feet (4.6 m - 6.7 m).

Ramp dozer plows and large special purpose plows are included in this category.

d. Extra Large Plow. This category includes plows with cutting edge lengths greater than 22 feet (6.7 m). This group also includes ramp dozer plows and extra large special purpose plows.

18. PLOW USES. Plows are most commonly mounted on the front of a carrier vehicle, but they may also be mounted on the side or underneath the vehicle.

a. Front-Mounted Plows.

1) One-Way Fixed Angle Plow. This unit is primarily used in large open area snowplowing operations that require a high-volume and high speed snow discharge at fixed left or right cutting angles.

2) Power Reversible Plow. This unit may be used for both large open area or confined area snowplowing operations. The design provides variable blade positions to either the right or left of the bulldozing position. This allows high volumes of snow to be displaced in a direction dictated by wind conditions or other constraints. The ability to reverse the plow angle improves operational efficiency and may reduce the number of plow units required.

3) Rollover Power Reversible Plow.

The primary use of this unit is for large open area snowplowing operations. High-speed and high volume snow discharge to either a right or left cutting angle may be achieved by rotating the blade assembly through 180° degrees. This type of plow is not recommended for bulldozing. The rollover concept reduces snow spillage by confining and spreading it through a tapered moldboard design.

4) Power Reversible Plow with Folding Wings. The primary use of this unit is for wide and extra wide swath snowplowing operations at various rates of speed. Cutting an extra wide swath may require a special carrier vehicle having high horsepower (see figure 3-2). When not in use, the wings should be designed to fold snugly against the carrier vehicle chassis.

5) Flexible Reversible Plow. This unit is made of polymer construction and is capable of changing its crossectional shape. It is versatile and can be used as a one-way fixed angle plow or a power reversible plow with the added feature that it can be adjusted to fit a variety of weather and snow conditions.

6) Ramp Dozer. This unit is primarily used in confined areas that require wide to extra-wide swath plowing, but it may also be used to transport and dump snow. The ramp blade is equipped with side plates to contain snow and prevent spillage. Removal of the moldboard cutting edge allows the moldboard to act as a bucket for snow loading.

7) Expressway Plow. This type of plow provides the speed characteristics of a rigid plow and the clean-up ability of a reversible plow. The plow has bulldozing capabilities, and if horizontally adjusted, it has the ability to cast snow to the right or left.�

AC 150/5220-20 6/30/92

8) Vee Plow. These plows are used for medium speed plowing operations through high drifts and heavy snow. Their acutely angled nose and swept wings will cast snow to the right and left simultaneously. In its articulated version, the plow operates at any angle along the arc of the wings from a fully closed "Vee" to one where the plow is extended to a near horizontal position.

b. Side-Mounted Wings.

1) Extension Wings. These attachments are mounted on either side of the carrier vehicle to increase the swath of the front-mounted plow. They are capable of high volume, high-speed snow removal operations.

2) Leveling Wings. These units operate with a front-mounted plow for windrow and snow bank leveling/trimming operations. The adjustable height of the leveling wing is designed to cast high drifted snow banks away from the cleared snow swath cut by the plow. They are designed for high-speed snow removal operations.

c. Underbody-Mounted Scraper. This unit is mounted behind the cab and on the underbody of a large truck or grader. During operation, constant ground pressure is applied by the scrapper blade on the pavement surface. The blade is capable of rotating its snow cast to either the left or right, thereby enhancing its ability to operate in confined areas.

19. MOLDBOARDS.

a. Geometric Design. The geometric design of a moldboard dictates the amount of snow that can be cast. A tapered moldboard or one with a flared end design or a moldboard that can change its contours will move larger amounts of snow higher and further than a moldboard of uniform height.

b. Non-metal Moldboards. Continuing development of non-metal moldboard materials may represent fuel savings because they are made of lighter weight polymers or other composites that will reduce snow/moldboard skin friction. Reductions in plow weights and skin friction reduce the power required to propel a snow plow unit, thereby reducing fuel consumption.

20. SNOW DEFLECTOR SHIELD. A snow deflector shield reduces snow spillage over the top of a moldboard by directing the air flow to the side toward the area of discharge. This helps to control the overhead snow plume created when traveling at high speed and thereby increases driver visibility.

21. CUTTING EDGES. Cutting edges may be made of either metal or nonmetal materials.

Nonmetal cutting edges conform better to irregularities in pavement surfaces which result in reduced edge wear and noise. Tungsten tipped carbide cutting edges, on the other hand, have greater longevity, even under severe operating conditions.

Only nonmetal cutting edges shall be used on pavements having in-pavement lighting.

22. PLOW SHOES AND CASTERS. The vertical separation between moldboard and pavement surface is determined by either plow shoes or caster wheels affixed to the moldboard reinforcing. These devices must be durable, reliable and able to perform without shimmy or damage to the pavement surface under all operating conditions.

The design shall allow the shoes or wheels to be easily replaced. Shoes are inappropriate for use on surfaces containing in-pavement lights. Caster wheels are preferred in these instances because they permit more precise separations between the moldboard cutting edge and the paved surface. They also conform better to pavement irregularities, have a lower cutting edge wear ratio, and are less noisy.

23. DISPLACEMENT PLOW/ROTARY PLOW

RELATIONSHIP. If heavy snow concentrations dictate a need for a rotary plow(s), the size and number of displacement plow(s) required to support the rotary plow may be determined through the use of figures 3-3 and 3-4.

24. DISPLACEMENT PLOW SELECTION.

Guidance on the selection of displacement plows may be found in Chapter 6.

25-26. RESERVED�

6/30/92 AC 150/5220-20

Figure 3-1.

Diferent Types �

AC 150/5220-20 6/30/92

LENGTH OF MOLDBOARD (ft) Figure 3-2. Carrier Vehicle Power versus Moldboard Length.

POWER (

bhp)�

6/30/92 AC 150/5220-20

Figure 3-3. Effective Displacement Plow Blade Length Related to Snow Displacement.

Q Displacement �

AC 150/5220-20 6/30/92

Figure 3-4. Effective versus Actual Displacement Plow Length.

“Efective” Blade Length (feet)�

6/30/92 AC 150/5220-20

This Figure Illustrates a Power Reversible Plow with All General Components. Details of Plow Components May Vary with Plow Manufacturer & with Type of Plow.

Figure 3-5. Displacement Plow Components.�

AC 150/5220-20 6/30/92

Area (1,000,000 x square feet) Figure 3-6. Snow Displacement (tons/hr.) Related to Surface Area.

Q Displacement (tons/hr)�

6/30/92 AC 150/5220-20

CHAPTER 4. MATERIAL SPREADERS.

27. DESCRIPTION. The function of a material spreader is to provide a continuous, unrestricted, accurately metered flow of granular or liquid material to a pavement surface over a predetermined spread area. Spreader units may be self-contained or they may be attached to a carrier vehicle. A spreader unit consists of a material storage compartment, a feed mechanism to carry the material to the discharge opening, a metering device to control the discharge rate, and a distribution mechanism.

Depending upon type, spreaders are capable of spreading dry and liquid chemicals and abrasives.

28. TYPES OF SPREADERS.

a. Dry Material Spreaders.

1) Conventional Hopper Spreaders.

Chassis mounted or slip in type hopper spreaders mount longitudinally between or directly over the carrier vehicle frame members. Hopper capacities for 4x6 and larger vehicles range from 5 to 17 yd3 (3.8 to 13.0 m3). Hopper capacities for pickup trucks up to one ton are from 0.75 to 2 yd3 (0.6 - 1.5 m3).

See figure 4-1 for typical dry material spreader types.

2) Multi-Purpose Dump Body Spreader. Multi-purpose dump body spreaders mount directly over the carrier vehicle frame members. The spreader may function as an elevating-dump body and as a material spreader.

Hopper capacity shall be between 5 and 17 yd3 (3.8 and 13.0 m3).

3) Tailgate Spreader. Tailgate spreaders mount on or under the tailgate of an elevating dump body. Hopper capacity is determined by the capacity of the dump body.

4) Towed Trailer Spreader. A trailer spreader is towed by a separate vehicle but has its own frame and suspension system. These dry material spreaders have a hopper capacity between 6 and 10 yd3 (4.6 and 7.6 m3).

b. Liquid Material Spreader. Liquid material spreaders may be self-contained or mounted on a carrier vehicle. Fluids are applied to pavement surfaces via a spray applicator system consisting of a supply tank, pump, flow rate monitor, and a spray bar equipped with nozzles. Tank capacities range from 500 to 4,000 gallons (1 900 to 15 200 liters).

29. DRY SPREADER SELECTION. Dry material spreaders shall be selected based on hopper capacity and the ability to apply material to a surface area at a predetermined application rate. A conventional slide-on spreader is adequate for most airport applications of dry chemicals. Special requirements, such as a need to haul bulk sand from a supplier, may justify alternative or multi-purpose types of spreaders, e.g. a tailgate spreader coupled with a dump truck body.

a. Hopper Capacity. Hopper capacity is determined by the material or combination of materials to be spread, the rate of application, and the area to be covered. Once the area to be treated is identified, the operator must determine the critical materials to be spread in order to properly size the hopper. Figures 4-2, 4-3, and 4-4 show the weight/volume relationship among sand, airside urea, and CMA based on several application rates.

b. Application rate. Material manufacturers recommend application rates for these products. By simply entering the appropriate graph, using the desired area to be covered and a recommended application rate, the weight/volume relationship can quickly be determined.

c. Example. An operator intends to apply airside urea as an anti-icer to a 6000 foot (1830 m) by 75 foot (23 m) runway at a rate of 2.0 ounces/yd2 (68 g/m2). Later, sand is to be applied to the same runway at a rate of 4.0 ounces/yd2 (136 g/m2). What is the hopper capacity of the spreader needed to treat the runway surface, and what is the spreader body length required to accommodate this capacity?�

AC 150/5220-20 6/30/92

Weight/volume Relationship of Sand and Urea Abrasive Weight of Volume of Material Material Sand 13,000 lbs.(5900 kg) 4.2 y3 (3.8 m3) Airside Urea 6,200 lbs.(2815 kg) 4.9 y3 (4.5 m3) In this case, the hopper capacity of the spreader should be at least 5.0 cubic yards to accommodate the critical urea material. The capacity chart below shows the standard inside spreader lengths necessary to accommodate volumes up to 17.2 cubic yards.

30. LIQUID SPREADER SELECTION.

Application rates of de/anti-icer fluids vary depending on ice and snow accumulations and overall weather conditions. They may be as low as

0.30 gal/1,000 ft2 (.01 l/m2) when anti-icing or as much as 1.0 gal/1,000 ft2 (.04 l/m2) when de-icing.

The size of the sprayer tank is a function of the square footage to be covered and the maximum fluid coverage rate to be applied. For example, assume that the critical primary surface area at an airport totals 700,000 ft2 (65 000 m2) and that the airport operator has determined that a fluid coverage rate of 1.0 gal/1,000 ft2 (.04 l/m2) will meet all but the most severe conditions with only one pass of the equipment. The minimum tank size needed would be:

700,000 ft2 x 1.0 gal/1,000 ft2 = 700 gals (65 000 m2 x .04 l/m2 = 2 600 l) Note: In selecting the size of a liquid spreader unit, the location of the storage tanks and the time it takes to reload the equipment with material must also be considered in the decision-making process.

31. DESIGN AND COMPONENT LAYOUT.

The design and installation of accessories shall permit easy access for maintenance, cleaning, and service. All components and assemblies shall be free of hazardous protrusions, sharp edges, and cracks.

Figure 4-6 illustrates design and component layout for a dry material spreader.

Table 4-1. SPREADER CAPACITY CHART.

Vertical Height (inches) Spreader Body Inside Length (feet) 8 9 10 11 12 13 14 15 16 48 4.5 5.1 5.6 6.2 6.8 7.3 7.9 8.4 8.9 54 5.5 6.2 6.9 7.6 8.4 9.0 9.7 10.3 11.0 60 6.5 7.4 8.3 9.0 9.9 10.7 11.6 12.2 13.0 66 9.5 10.3 11.5 12.3 13.5 14.2 15.1 72 11.9 13.0 14.0 15.3 16.1 17.2 72 84 84 96 96 102 108 120 126 Recommended Truck Cab to Axle Length (inches)

32-33. RESERVED.�

6/30/92 AC 150/5220-20

Figure 4-1. Dry Material Spreader Types.�

AC 150/5220-20 6/30/92

RUNWAY LENGTH (Thousands of feet)—75’Swath Width Figure 4-2. Hopper Capacity—Sand.

VOLUME (Cubic �

6/30/92 AC 150/5220-20

RUNWAY LENGTH (Thousands of feet)—75’ Swath Width Figure 4-3. Hopper Capacity—Urea.�

AC 150/5220-20 6/30/92

RUNWAY LENGTH (Thousands of feet)—75’ Swath Width Figure 4-4. Hopper Capacity—CMA.�

6/30/92 AC 150/5220-20

25 (and 26) This figure depits the general layout of a dry hopper system having a hydraulic or mechanical drive, a belt or chain type conveyor, and a dual spinner spreader. Some optional recommended devices are also depicted. Other spreader configuations may contain components differing indesign, but essentially perfoorming the same function.

Figure 4-5. General Design and Component Layout of a Dry Material Spreader.�

6/30/92 AC 150/5220-20

27 (and 28)

CHAPTER 5. CARRIER VEHICLES.

34. DESCRIPTION. The term carrier vehicle represents the various self-propelled prime movers that provide the power necessary to move snow and ice control equipment during winter operations.

Vehicle selection is determined by the mission to be performed and the capacity of the selected equipment.

a. Truck Type Vehicles. Truck type vehicles are standard production models designed primarily to meet an airport's snow and ice control needs but also have the ability to perform secondary functions.

They may be self-contained, designed specifically for a singular purpose, or they may be multifunctional and equipped for several summer as well as winter tasks. They should conform to the manufacturer's recommendations and be suitable for mounting all specified accessories.

b. Special Purpose Vehicles. Special purpose vehicles are customized specifically to meet special airport needs such as high-volume and/or extra wide swath clearing operations.

c. Wheel Loader Vehicles. Wheel loaders are standard production four-wheel drive articulated and non-articulated vehicles, normally equipped with a front-mounted bucket, that operate at low speeds of 5 to 20 mph (8 to 30 km/h). They are very efficient for short haul operations and are used to clear compacted snow and ice from heavily used ramp and terminal areas and around pavement lights. A wheel loader will generally out-perform a truckmounted displacement plow in such confined areas, but it is not as efficient when large open areas need to be cleared quickly. Other applications include snow loading and stockpiling and loading of solid chemicals and abrasives.

d. Industrial 4x4 Tractor Vehicles.

Industrial 4x4 tractors are standard production models adapted for snow and ice control work in confined areas. While similar to wheel loaders, most are built to operate at higher speeds.

e. Vehicle Dimension. Vehicle dimensions shown in appendix 1 will permit vehicles to pass through the standard industrial door openings of service and storage buildings (AC 150/5220-18, Buildings for Storage and Maintenance of Airport Snow and Ice Control Equipment and Materials).

These dimensions are also compatible with FAA recommended parking space set-asides within these buildings. Additionally, they should permit servicing of equipment by standard lifts and cranes without special equipment or building modification.

35-36. RESERVED.�

6/30/92 AC 150/5220-20

CHAPTER 6. SELECTION OF ROTARY AND DISPLACEMENT PLOWS.

37. DESCRIPTION. This chapter provides guidance in the selection of rotary and displacement plows under varying winter operational conditions.

It is intended to familiarize the operator with the graphs and tables discussed earlier for use in determining displacement plow geometrics and rotary plow capacities. Several practical examples are discussed including a mathematical analyses that involves a number of variables including snow density, plow efficiency, and equipment speed.

38. MINIMUM EQUIPMENT

REQUIREMENTS.

a. Commercial Service Airports. For commercial service airports that provide scheduled air carrier service and experience snow conditions as presented in AC 150/5200-30A, at least one highspeed rotary snowplow is recommended. This plow should be supplemented with at least two displacement plows having equal capacity. In addition to this equipment, for each 750,000 ft2 (70 000 m2) of primary pavement area, one towed or self propelled air-blast power sweeper and one hopper spreader for abrasives and solid de-icing chemical should be provided. If liquid de-icing chemical is used in lieu of, or in addition to, solid chemical, a minimum of one liquid spreader vehicle is recommended.

b. Non-commercial Service Airports. For non-commercial service airports having 10,000 or fewer annual operations and an annual snowfall of 30 inches (.76 m) or less, a minimum of one displacement plow should be provided. Airports having more than 30 inches (.76 m) of snow or those with over 10,000 operations and at least 15 inches (.38 m) of snow should have a minimum of one high-speed rotary plow supported by two displacement plows of equal capacity.

c. Supporting Equipment. Support vehicles such as sweepers and wheel loaders are usually needed to complete the removal of snow from all operational areas including secondary runways, taxiways, and ramp aprons.

39. DISPLACEMENT PLOW/VEHICLE

COMPATIBILITY. A displacement plow must be properly paired with its carrier vehicle to achieve maximum operational performance. The level of performance between the two units is directly proportional to the type, size and weight of the plow and the power and weight of the vehicle. Figure 3-2, Carrier Vehicle Power versus Moldboard Length, provides a graphical representation of the vehicle power/displacement plow length relationship.

40. SELECTING A ROTARY PLOW FOR

COMMERCIAL AND NON-COMMERCIAL

SERVICE AIRPORTS.

In this example, an airport operator of a commercial service airport having an annual activity level of 35,000 operations wants to acquire a rotary plow for the upcoming winter season. Determine the size of the rotary plow needed based on the following conditions:

a. The airport snowplan calls for removal operations to begin when one inch of snow accumulates on the runway.

b. AC 150/5200-30A states that the primary surface area of this airport should be cleared in one hour.

c. Snow density is 25 lb/ft3 (400 kg/m3)-industry accepted standard.

GRAPHICAL SOLUTION

Step 1. Determine the size of the primary area to be cleared.

Location Area Main runway (9000 ft x 150 ft) 1,350,000 ft 2 Taxiways 187,000 Fillets 20,000 AARF apron and roads 20,000 Apron 40,000 Blast pads 60,000 Miscellaneous 20,000 Total primary area to be cleared 1,697,000 ft 2 Note: For calculation purposes, the area may be rounded off to 1,700,000 ft2 (158 000 m2).�

AC 150/5220-20 6/30/92

Step 2. Use of Graphs.

Figure 2-5, Rotary Plow Calculations for Airports with Commercial Service, indicates that nearly 2,500 tons of snow per hour will have to be moved.

Using either Figure 2-5 or Table 2-1, Rotary Plow Capacities, the following solutions are possible depending on the snow casting distance desired:

Class of plow Casting Distance No. plows needed (ft/m)

II 75/22.9 2

III 100/30.5 1

For non commercial airports, the same procedure holds, but the graph shown in Figure 2-4, Rotary Plow Calculations for Airports Without Commercial Service, should be used.

MATHEMATICAL SOLUTION

Figures 2-4 and 2-5 were developed from the following calculations and either procedure, graphical or mathematical, can be used in determining equipment selection. The mathematical solution is a little more flexible because it is capable of considering variables such as snow depth, snow density, and rotary plow efficiency that the graphical solution treats as industry accepted standards.

In this example, an airport operator of a commercial service airport prefers to clear the primary area in 40 minutes and needs to acquire a new rotary plow capable of casting snow at least 75 feet (22.9 m).

The operator feels that local weather conditions are unique and that snow weighing 30 lb/ft3 (480 kg/m3) is typical. The operator also wants a rotary plow having an efficiency rating of 75 percent. What size rotary plow should be purchased?

Step 1. Determine size of area to be cleared (Use same procedure as step 1 above) Step 2. Determine rate of snow to be cleared (tons/h).

Calculations 1,700,000 ft 2 x 1/12 ft = 141,666 ft 3 141,666 ft 3 x 30 lb/ft 3 = 4,249,980 lbs.

4,249,980 lbs ¸ 0.75 (eff.) = 5,666,640 lbs.

5,666,640 lbs. ¸ .67 h (40 min) = 8,457,672 lbs/h 8,457,672 lbs/h ¸ 2,000 lbs/ton = 4,229 tons/h Step 3. Use of table 2-1 Snow removal requirements are approximately 4,300 tons per hour. Table 2-1 shows that several rotary plow combinations are possible. In this case, a Class IV rotary plow working in conjunction with a Class II plow is a possible combination. A single Class V plow is also a possibility, particularly since the required casting distance is only 75 feet (22.9 m).

Obviously, there are several combinations that should be considered to assure the best use of equipment.

For non-commercial service airports, the mathematical procedure remains the same. The difference lies in the fact that the timing to clear the primary area of a commercial service airport is different from that of a non-commercial service airport. These times can be found in AC 150/5200- 30A.

41. SELECTING A DISPLACEMENT PLOW

BLADE LENGTH.

This section presents a graphical and mathematical procedure that may be used to determine the length of a displacement plow blade under various operational conditions. It should be pointed out that the process of selecting a plow blade is not an exact science and that different manufacturers may suggest alternative approaches tailored to their equipment, but the results should essentially be the same.�

6/30/92 AC 150/5220-20

GRAPHICAL SOLUTION

Find the actual displacement plow blade length needed to clear one inch of snow in one hour from the primary surface area discussed above. Determine if the selected plow can be attached to an available carrier vehicle having 300 brake horsepower (bhp) which is designed to carry heavy front end loadings and if not, what are options available to the operator?

The average operating speed of the plow unit must be at least 20 mph (32 kph) to meet the clearance times discussed in AC 150/5200-30A. The efficiency of the snowplow is 70 percent and the cutting angle of the blade will be set at 35°.

Step 1. Determine the size of the area to be cleared.

(See step 1, para. 40 - graphical solution).

Step 2. Snow Displacement. Figure 3-6, Snow Displacement Related to Surface Area, shows that a snowplow working at a 70 percent efficiency level would have to displace about 2,500 tons of snow in one hour to clear the area.

Step 3. Effective Blade Length. Figure 3-3, Effective Displacement Plow Blade Length Related to Snow Displacement, shows that it would take an effective blade length of 23.0 feet (7.0 m) operating at 20 mph (32 kph) to displace 2,500 tons of snow in one hour.

Step 4. Actual Blade Length. In order to cut a

23.0 foot (7.0 m) wide swath with blade angle set at 35°, Figure 3-4, Effective Versus Actual Displacement Plow Blade Length, shows that a plow blade of 30.0 feet (9.1 m) would be required.

Step 5. Plow Selection. Figure 3-2, Carrier Vehicle Power versus Moldboard Length, shows that a vehicle having 300 bhp is only capable of accommodating a 18-23.0 foot (5.5-7.0 m) plow, depending upon plow and vehicle manufacture. At this point the operating official has several options available:

a) Acquire a carrier vehicle of about 400-500 bhp, figure 3-2, to accommodate the 30 foot plow.

The 300 bhp vehicle would then be available for other purposes. This move would have to be carefully analyzed due to the size and cost of equipment involved and the cost of operation, or

b) Match the 300 bhp vehicle to a displacement plow of acceptable length (between 18-

23.0 feet (5.5-7.0 m) say 20 feet (6.1 m) and acquire a second vehicle to accommodate the remaining

10.0 foot (3.0 m) blade still needed (30.0-20.0 = 10.0) (9.1-6.1 = 3.0 m), or

c) select any combination of possibilities that may or may not incorporate the 300 bhp vehicle.�

AC 150/5220-20 6/30/92

MATHEMATICAL SOLUTION

The mathematical approach, similar to the one used earlier with rotary plows, provides flexibility in determining blade size because each variable is considered in the solution.

In this example, an airport operator of a large commercial service airport wants to acquire a new displacement plow to more efficiently meet the capability of an existing 2500 ton rotary plow. For calculation purposes, the operator assumes the following local conditions:

CALCULATIONS

a. Snow accumulation (d) 1 inches

b. Snow density (p) 30 lbs/ft3

c. Rotary plow capacity (Q) 2500 tons/h

d. Operating speed (v) 20 mph

e. Rotary plow efficiency eff (b) 70 %

f. Displacement plow efficiency eff (p) 75 %

g. Displacement plow cutting angle (a) 30 degrees 12 in/ft x 2000 lbs/ton

h. Conversion factor (4.545) = 5280 ft/mile

i. Effective blade length (eb) Q x Eff(b) eb = x 4.545 d x v x p Eff(p) 2500 x 0.70 eb = x 4.545 1 x 20 x 30 x 0.75 eb = 17.67 feet

j. Actual blade length (ab) eb ab = cosine a 17.67 ab = cosine 30 ab = 20.4 feet

k. Displacement plow selection. The airport operator would select a 21.0 foot displacement plow to support the 2500 ton rotary plow.

42-43. RESERVED.�

6/30/92 AC 150/5220-20

CHAPTER 7. OPERATIONAL STANDARDS AND TESTING.

44. GENERAL. The manufacturer shall be responsible for conducting tests to ensure that its snow and ice control equipment meets the operational and performance requirements it advertises. Certified records of these compliance tests shall be submitted by the manufacturer with each response to an invitation to bid. Equipment tests shall be conducted on standard production models and not on specially constructed prototypes.

45. ADDITIONAL TESTS. The purchaser should consider conducting its own operational, performance, and capacity tests on equipment prior to acceptance. The manufacturer should have the opportunity to witness the performance of these tests, but interpretation of results is the sole responsibility of the purchaser.

46. CARRIER VEHICLE TESTS. The following temperature, performance, and compliance tests may be conducted by a purchaser when acquiring a carrier vehicle.

a. Cold Weather Operations. A fullyequipped carrier vehicle should be able to perform normal operations at an ambient temperature of:

1) 10°F (-12°C) below the lowest temperature in which the vehicle is expected to operate, or

2) -40°F (-40°C) at airports located in extremely cold climates.

b. Hot Weather Operations. The vehicle should be capable of operating at an ambient temperature of 70°F (21°C) at the maximum speed recommended by the manufacturer without any of the vehicle components exceeding their normal operating temperature.

c. Power. Carrier vehicles shall have sufficient power to perform all operational and attached functions simultaneously.

d. Performance. The following tests shall be conducted on a vehicle loaded to its GVW ( Gross Vehicle Weight) and shall include the following systems: hydraulic, power train, brake, lighting, controls, and instruments.

1) 10 Mile Test. This test requires that the vehicle be driven over hard surfaced roads at normal airport speeds for a distance of 10 miles (16 km) with no perceptive problems. Special attention shall be focused on vibration, steering, vehicle drift, rattles, leaks, and interior controls.

2) One Hour Test. This is a time test that will be performed at a speed of 5 mph (8 kph) over all types of terrain that would normally be encountered at the airport.

3) Service Brake Test. This test shall be conducted at speeds of 20 mph and 40 mph (32 kph and 64 kph) respectively. Using the service brakes only, the fully loaded vehicle shall be brought to a complete stop within a distance of 35 and 131 feet (11 and 40 m) measured from the point of brake application. The test shall be conducted for two complete cycles in either direction on a hard pavement surface that is dry, reasonably level and free of loose material. During this maneuver, no steering corrections shall be made for vehicle drift during the stop.

4) Emergency Brake Test. This test shall be conducted at a speed of 40 mph (64 kph).

Using the emergency brake only, the fully loaded vehicle shall be brought to a complete stop on the most critical airfield pavement grade within a distance of 288 feet (88 m) measured from the point of brake application. The test shall be conducted on a hard surface that is dry and free of loose material.

Once stopped, the brake will continue to hold the vehicle without fade for five minutes. During this maneuver no steering corrections shall be made for vehicle drift during the stop.�

AC 150/5220-20 6/30/92

47. ROTARY PLOW TEST. Rotary plow capacity and casting distance may be verified in the following manner:

a. Preparation of Test.

1) The testing official shall select a suitable site, preferably a flat, paved surface. A triangular shaped windrow made of fresh undisturbed snow shall be constructed on the site having a base of 10 feet (3 m) or a width conforming to equipment width (whichever is smaller), a minimum height of four (4) feet (1.2 m), and an average cross sectional area of at least 20 ft2 (1.9 m2). The snow density should be in the range of 25 to 30 lb/ft3 (400 to 480 kg/m3). The windrow should have a minimum length of 500 feet (150 m) and be made of relatively fresh snow that has not had an opportunity to melt or refreeze. Because the shear strength of snow changes with time, it is recommended that the test be started within one hour of windrow construction.

2) Equipment needed for the test is a 100 foot measuring tape, a thermometer, a stop watch, and a snow density measuring kit (Taylor LaChapelle or Kelly Snow Density Cutter).

3) During the test, the rotary plow should be operated at an engine temperature recommended by the manufacturer. The operator conducting the test should be familiar with the vehicle and the test procedure.

b. Measurement.

1) The cross sectional area of the windrow should be measured at the beginning, the end, and at 100 foot stations along the longitudinal centerline to ensure uniformity.

2) Snow density samples shall be taken at the base, middle, and top of these station locations.

The average of their densities will become the average density of the windrow.

3) The test shall be run along the windrow in accordance with the manufacturer's recommended operating procedure to obtain maximum capacity and casting distance.

4) Capacity Calculations. The capacity of the rotary plow can now be calculated using the following formula:

Q = A x L x D x 1.8/t Where: Q = Capacity (tons/hour) A = Average cross sectional area of windrow (ft2) L = Length of windrow (ft) D = Average density of snow in lb/ft3 t = Time of test run measured in seconds

c. Casting Distance. The casting distance is determined in accordance with guidance shown in Chapter 2, paragraph 12.

d. Additional Visual Tests. During the capacity tests, the rotary snowplow may also be visually evaluated. The swath that is cut should be even and regular and show less then 5 percent snow spillage.

48. DISPLACEMENT PLOW CAPACITY

TEST. A displacement plow that is attached to a properly sized carrier vehicle, except for industrial 4x4 tractors and wheel loaders, should:

a. be capable of sustaining a speed of 25 mph (40 kph) on level pavement with plow angle set at 37° while negotiating a 3 to 6 inch (7.6 to 15.2 cm) snow accumulation having a density of approximately 25 lb/ft3 (400 kg/m3).

b. be able to discharge snow to either side of the vehicle while moving (if the unit is power reversible).

c. minimize snow spillover to 5 percent of total snow displaced.

d. be able to produce a clear swath that is even, regular and non-skipping.

e. be relatively free of blade vibration during operation.

49. SPREADER TEST. Material spreaders may be field tested to determine performance as follows:

a. Liquid and dry spreader. Liquid and dry spreader settings for swath width and application rate should be verifiable by field measurements to an accuracy of 2 percent under a no wind condition.

b. Towed spreaders. Towed spreaders should not vibrate excessively during operation and braking.�

6/30/92 AC 150/5220-20

Appendix 1

APPENDIX 1 - SPECIFICATION FOR CARRIER VEHICLE.

PART A - AIRPORT OPERATOR CHECKLIST.

FORWARD: When preparing a solicitation to purchase a carrier vehicle, an airport operator or specification writer should use PART A to identify user requirements and PART B to define the specification to meet these requirements. Part A is important because it tailors the carrier vehicle to the unique requirements of the purchaser, i.e. automatic versus manual transmission, gasoline versus diesel, grooved windshield versus plain etc. Both parts, when combined, become the technical basis for a users request for proposal.

1. Anticipated uses and/or features of vehicle. (Be Specific)

2. Performance Requirements.

a. Required Working Speed

b. Minimum Speed

c. Turning Radius

3. Engine/Transmission.

a. Automatic .........................................................Manual

b. Gasoline............................................................Diesel

c. Number of forward speeds

4. Transfer case. (choose one)

a. Single speed ......................................................Two speed

b. Front axle disconnect Automatic locking differential Manual locking differential

5. Axle capacities. Front .........................................Rear

6. Fuel capacity........................................................gallons

7. Auxiliary equipment. (see Appendix 2)

AC 150/5220-20 6/30/92

Appendix 1

PART B - SPECIFICATION FOR CARRIER VEHICLE.

1. MATERIALS. Materials used on a carrier vehicle (vehicle) shall conform to the specifications listed in this advisory circular and appropriate sections of Title 49, Chapter III, Subchapter B - Federal Motor Carrier Safety Regulations (Title 49). When not specifically listed, materials shall be of the best quality available for their intended commercial use. Component parts shall be new and free of all defects and imperfections that could affect the serviceability of the finished product.

2. DESIGN. Equipment shall be developed in accordance with the best engineering practices available. This includes the incorporation of ergonomic designs specifically directed at the vehicles cab environment. Vehicle design shall include current state-of-the-art procedures that consider improved cab visibility, communications systems, interior lighting and the mitigation of noise and vibration. Design and installation of equipment shall permit easy accessibility for maintenance and service. All vehicle stress points shall be designed to distribute and dissipate shock forces.

3. CONSTRUCTION. Vehicle construction shall provide maximum protection against structural member failures. Equipment shall withstand the cold, moisture, strains, jars, vibration, and other conditions that are likely to be encountered during operation. All components and assemblies shall be free of hazardous protrusions, sharp edges, cracks, or other elements which might cause injury to personnel or damage to equipment. Location of all oil, hydraulic, and air lines and electrical wiring shall be in protected positions properly attached to the frame or body structure. Wherever these lines pass through structural members, they shall be protected with looms or grommets except where a through-frame connector is necessary.

4. CHASSIS.

a. GENERAL. The design of the vehicle chassis shall be based on an all-wheel drive concept for optimized performance and safety. It shall have power assisted steering and a transmission with suitable load ranges to accommodate normal operating conditions. A pintle hook shall be permanently attached to the rear frame structure capable of towing a vehicle. All installed parts and accessories necessary for the safe operation of the vehicle shall conform to applicable provisions of Title 49.

b. Structural Members. The frame shall be made of either pressed or structural steel channel and reinforced as required to prevent distortion under…