+----------------------------------+----------------+-----------------+
| ![](media/image1.png)            | **Advisory     |                 |
| {width="1.0416666666666666e-2in" | Circular**     |                 |
| h                                |                |                 |
| eight="1.0416666666666666e-2in"} |                |                 |
| ![](media/image2.wmf)            |                |                 |
|                                  |                |                 |
| U.S. Department                  |                |                 |
|                                  |                |                 |
| of Transportation                |                |                 |
|                                  |                |                 |
| **Federal Aviation**             |                |                 |
|                                  |                |                 |
| **Administration**               |                |                 |
+----------------------------------+----------------+-----------------+
| **Subject:** DESIGN OF AIRCRAFT  | **Date:**      | **AC No:**      |
| DEICING FACILITIES               | 2/5/2008       | 150/5300-14B    |
|                                  |                |                 |
|                                  | **Initiated    | **Change:**     |
|                                  | by:** AAS-100  |                 |
+----------------------------------+----------------+-----------------+

**1. PURPOSE.** This advisory circular (AC) provides standards,
specifications, and guidance for designing aircraft deicing facilities.

**2. APPLICATION.** The FAA recommends the guidelines and standards in
this AC for aircraft deicing facilities. This AC does not constitute a
regulation and in general is not mandatory. However, use of these
guidelines is mandatory for aircraft deicing facilities funded under the
Airport Improvement Program (AIP) and Passenger Facility Charge (PFC)
Program. Mandatory terms such as "must" used herein apply only to those
who establish aircraft deicing facilities using AIP or PFC funds.

**3. CANCELLATION.** This AC cancels AC 150/5300-14A, *Design of
Aircraft Deicing Facilities,* dated September 18, 2007.

**4. PRINCIPAL CHANGES.**

**a. Paragraph 3-2, Separation Standards for Off-gate Aircraft Deicing
Pads,** includes revised text related to a new table 3-1. The revision
seeks to reduce accident/incident rates associated with ground
deicing/anti-icing operations at deicing pads. The design of permanent
deicing facilities calls for the inclusion of vehicle safety zones and
vehicle maneuvering areas for deicing pads. The 10-foot (3 m) dimension
for the width of the vehicle safety zone is the industry consensus and
is recommended by the *SAE G-12, Aircraft Ground Deicing/Anti-icing
Committee, Subcommittee for Design and Operations of Aircraft Ground
Deicing Facilities.* In addition, National Transportation Safety Board
(NTSB) "Factual Reports" support the need for this revision. Examples
include NYCC06LA074 \[February 25, 2006\], DEN06IA034 \[January 19,
2006\], and DEN06IA008

\[October 10, 2005\]. These reports are available from the NTSB Accident
Database (<http://www.ntsb.gov/ntsb/>).

**b.** **New Table 3-1.**

**(1)** Combines and updates former tables 3-1 and 3-2 to offer airport
operators the option to locate off-gate deicing facilities in the
movement area or non-movement areas (columns #4 and 5). Column #4,
off-gate deicing facilities with vehicle safety zones, was added to
allocate sufficient separation between deicing pads where the deicing
facility will eventually be converted into a permanent off-gate deicing
facility. Column #5, off-gate deicing facilities without vehicle safety
zones, continues to reflect the practice by airport operators to
designate on a temporary basis the use of apron areas, near a departure
runway or adjacent to terminal gates, for deicing/anti-icing airplanes.
Temporary off-gate deicing facilities may have vehicle safety zones, but
they generally lack the on-site infrastructure that is associated with
permanent off-gate deicing facilities, such as a snow control center,
crew shelter, overhead lighting, or electronic message boards.

**(2)** Resolves insufficient space between vehicle maneuvering areas,
vehicle safety zones, and parked airplanes that may exist for several
airplane design groups when applying only taxilane criteria from AC
150/5300-13, *Airport Design*.

**(3)** Provides five equations, one per each of the five scenarios in
the new table 3-1, that may be used for the justification of a
modification of standard that provides an acceptable level of safety to
the recommended separation standard. The use of an equation incurs an
operational limitation on permitted wingspan for a given deicing pad.

![](media/image3.jpeg){width="2.4895833333333335in"
height="0.8645833333333334in"}

Wayne T. Heibeck

Acting Director of Airport Safety and Standards

## This page intentionally blank.

CONTENTS

CHAPTER 1. INTRODUCTION

[Paragraph]{.underline} [Page]{.underline}

1-1. Overview 1

1-2. Definitions 1

1-3. Project Input 2

1-4. Related Reading Material 2

CHAPTER 2. SIZING AND SITING DEICING FACILITIES

2-1. General 3

2-2. FAA Clearance and Separation Standards Affecting Deicing Facilities
3

2-3. Capacity of Deicing Facilities 4

2-4. Factors Affecting Number of Aircraft Deicing Pads and Deicing
Facilities 4

2-5. Factors Affecting Facility Location and Size 5

2-6. Fluid Handling Requirements at Deicing Facilities 6

2-7. Nighttime Lighting 6

2-8. Bypass Taxiing Capability 6

2-9. Multiple Deicing Queues 6

2-10 Topography 6

2-11 Utilities 7

2-12. The Airport Layout Plan (ALP) and Sizing and Siting Facilities 7

CHAPTER 3. DESIGN OF AIRCRAFT DEICING PADS

3-1. Aircraft Deicing Pads 9

3-2. Separation Standards for Off-gate Aircraft Deicing Pads 9

3-3. Fixed Fluid Applicators 9

3-4. Pavement Markings for Off-gate Deicing Facilities 9

3-5. Deicing Pad Layouts 11

3-6. Electronic Message Boards for Off-gate Deicing Facilities 15

3-7 Apron Designs for Off-gate Deicing Facilities 15

CHAPTER 4. AIRCRAFT ACCESS AND VEHICLE SERVICE ROADS

4-1. Aircraft Access Routes 19

4-2. Vehicle Service Roads 19

CHAPTER 5. DESIGN OF INFRA-RED AIRCRAFT DEICING FACILITIES

5-1. Overview 21

5-2. Design Airplane 21

5-3. Infra-red Deicing Facilities (IDFs) 21

[Paragraph]{.underline} [Page]{.underline}

5-4. Siting of Infra-red Deicing Facilities 21

5-5. Entrance Taxiway 22

5-6. Infra-red Deicing Structure 22

5-7. Nighttime Lighting 23

5-8. Sizing Infra-red Deicing Structures 23

5-9. Optional Equipment -- Ice Detection Cameras 24

5-10. Facility Operations Shelter 25

5-11. Computer-Controlled Gas-Powered Infra-red EU Systems 25

5-12. Installation of Infra-red EU Systems 27

5-13. Infra-red EU System Configuration 27

5-14. Computer Hardware/Performance 27

5-15. Anti-icing Capability 28

5-16. Exit Taxiway 28

5-17. Bypass Taxiing Capability 28

5-18. Runoff Mitigation 28

CHAPTER 6. WATER QUALITY MITIGATION

6-1. Runoff Mitigation Structures 29

6-2. Mitigation Alternatives 29

6-3. Publicly Owned Treatment Works (POTWs) 29

6-4. Detention Basins 30

6-5. Underground Storage Tanks (USTs) 30

6-6. Recycling Glycol Fluids 30

6-7. Anaerobic Bioremediation Systems 31

FIGURES

Figure 1-1. Aircraft deicing pad with vehicle maneuvering area 2

Figure 2-1. Separate taxiing entrance to an aircraft deicing facility 7

Figure 3-1(a). Facility taxiway/taxiway holding position marking 12

Figure 3-1(b). Deicing pad identification ("B5") surface marking at
entrance point 12

Figure 3-1(c). Vehicle safety zone surface marking standards 13

Figure 3-2. Example of a common deicing pad layout 14

Figure 3-3. Example of a composite deicing pad layout 14

Figure 3-4. Deicing pad centerlines oriented 45 degrees with the
connecting taxiway 14

Figure 3-5(a). Electronic message board instructing the pilot to
continue forward to the stop point of the deicing pad 16

Figure 3-5(b). Electronic message board informing the pilot the aircraft
has reached the stop point of the deicing pad 16

Figure 3-5(c). An electronic message board *alternating information* to
the aircraft receiving deicing/anti-icing treatment 17

Figure 5-1. FAA Boeing 727-100 taxiing into an infra-red deicing
facility 22

TABLES

Table 3-1. Separation criteria for off-gate aircraft deicing pads having
parallel taxiways 10

Table 5-1. Protective cover lengths 24

Table 5-2. Horizontal clearances 24

Table 5-3. Acceptance criteria for contamination removal by infra-red EU
systems 27

**CHAPTER 1. INTRODUCTION**

**1-1**. **OVERVIEW.** Safe and efficient aircraft operations are of
primary importance in the development of any aircraft deicing facility.
This AC discusses sizing, siting, environmental runoff mitigation, and
operational needs of a deicing facility and how to maximize deicing
capacity while maintaining maximum safety and efficiency. Airport
managers can construct, within FAA standards, deicing facilities at
terminals, on apron areas, taxiways or near departure runways.
Furthermore, there are a number of operations issues associated with
off-gate deicing facilities that should be evaluated. The Society of
Automotive Engineers (SAE) Aerospace Division publication Aerospace
Recommended Practice (ARP) 4902, *Design and Operation of Aircraft
Deicing Facilities,* provides a list of operational issues that SAE
recommends addressing. It is preferable that the facility's service
provider follow, if possible, one agreed-upon deicing/anti-icing
procedure for all users of the facility. One common procedure must
minimize the confusion that can occur when several users prescribe a
wide range of requirements. The airport operator should address such
issues prior to the design of the facility to ensure the facility's
safety benefits can be achieved in an operationally efficient and
cost-effective manner.

**a. Role of Deicing Facility.** The design of deicing facilities
should, to the extent practicable, meet the needs of air carriers, as
outlined in FAA-approved aircraft ground deicing/anti-icing programs,
and all other aviation community users. A key element in this effort is
designing a facility that is efficient and offers users operational
flexibility. Coordination of an airport authority's Snow and Ice Control
Plan and user's ground deicing/anti-icing programs, with input from the
FAA, will ensure icing conditions affecting the safety of flight are
better met.

**b. Design Flexibility.** This AC identifies aircraft deicing
facilities as being either centralized or remote (see paragraphs 1-2(b)
and 1-2(c)).

**(1) Centralized Deicing Facilities.** Centralized deicing facilities,
where aircraft receive deicing/anti-icing treatment, can be constructed
at numerous sites with increasing constraints toward departure runways.
A terminal, for example, is a centralized deicing facility; the gates
serve as aircraft deicing pads for deicing/anti-icing operations. Gate
areas that cannot meet storm water permitting regulations but can
adequately handle deicing/anti-icing demands of users and allow
acceptable taxiing times to the departure runway under varying weather
conditions should, if practicable, be upgraded environmentally.

**(2) Remote Deicing Facilities.** Remote deicing facilities allow
aircraft to receive deicing/anti-icing treatment. Siting remote
facilities near departure runways minimizes the taxiing time between
treatment and takeoff. Such facilities also compensate for changing
weather conditions when icing conditions or blowing snow are expected to
occur along the taxi route taken by aircraft to the departure runway.

**1-2. DEFINITIONS.**

**a. Aircraft Deicing Facility.** An aircraft deicing facility is a
facility where---

**(1)** frost, ice, slush, or snow is removed (deicing) from the
aircraft in order to provide clean surfaces, and/or

**(2)** clean surfaces of the aircraft receive protection (anti-icing)
against the formation of frost or ice and accumulation of snow or slush
for a limited period of time (referred to as the "holdover time").

**b**. **Centralized Deicing Facility.** A centralized deicing facility
is an aircraft deicing facility located at the terminal gates/aprons or
along taxiways serving departure runways.

**c**. **Remote Deicing Facility.** A remote deicing facility is an
aircraft deicing facility located along taxiways serving departure
runways or near the departure end of runways.

**d**. **Aircraft Deicing Pad.** An aircraft deicing pad consists of two
areas (see figure 1-1):

**(1)** inner area for the parking of aircraft to receive
deicing/anti-icing treatment, and

**(2)** outer area for maneuvering two or more mobile deicing vehicles.

**e. Holdover Time.** Holdover time is the ***estimated*** time the
application of anti-icing fluid will prevent the formation of frozen
contamination on the protected surfaces of an aircraft. With a one-step
deicing/anti-icing operation, the holdover begins at the start of the
operation; with a two-step operation, at the start of the final
anti-icing application. Holdover time will have effectively run out when
frozen deposits start to form/accumulate on the treated aircraft
surfaces. For departure planning purposes, holdover time guidelines for
various anti-icers---such as Types I, II, and IV---are published.
Guidelines for holdover times can be found in

SAE ARP 4737, *Aircraft Deicing/Anti-icing Methods with*

*Fluids.* The Association of European Airlines (AEA)

notes, *"Due to the many variables that can influence*

*holdover times, these times should not be considered minimum or maximum
as the actual time of protection may be reduced or extended, depending
upon particular conditions existing at the time."*

![](media/image4.png){width="3.982638888888889in"
height="1.9270833333333333in"}

**Figure 1-1. Aircraft deicing pad with vehicle maneuvering area**

**1-3. PROJECT INPUT.** Because each airport is unique,
deicing/anti-icing needs of users are better addressed when affected
parties help identify the requirements for deicing facilities.

**a. Affected Parties.** Airport management should solicit input from
the following parties:

**(1)** FAA Air Traffic Control, Airports Division, Technical
Operations, and Flight Standards Offices,

**(2)** airport operations chief, environmental manager, and the
aircraft rescue and fire fighting chief,

**(3)** station/operations managers of tenant air carrier and regional
or commuter air carriers,

**(4)** pilot organizations or representatives, air taxis, and general
aviation users,

**(5)** ground deicing managers of air carrier, regional or commuter air
carriers, and/or the fixed base operator contracted with the
responsibility,

**(6)** engineering contractor, and

**(7)** other parties at the discretion of airport management.

**b**. **Other.** The FAA recommends that airports involve or inform
Federal, state, and local environmental authorities having jurisdiction
early in the facility development process to ensure compliance with
storm water permitting requirements. Review of deicing facility plans by
environmental authorities is a significant step toward compliance with
U.S. Environmental Protection Agency National Pollutant Discharge
Elimination System (NPDES) storm water permitting requirements.

**1-4. RELATED READING MATERIAL.** Publications referenced in this AC
are available from the following organizations:

**a. FAA ACs,** [www.faa.gov](http://www.faa.gov/).

**b. Society of Automotive Engineers (SAE),** 400 Commonwealth Drive,
Warrendale, PA 15096-0001, or [www.sae.org](http://www.sae.org/).

**c.** **The International Organization for Standardization,** Case
Postal 56, Rue de Varembe, CH-1211 Geneva 20, Switzerland, or
[www.iso.org](http://www.iso.org/).

**d.** **National Fire Protection Association (NFPA),** 1 Batterymarch
Park, Quincy, MA 02169-7471, or [www.nfpa.org](http://www.nfpa.org/).

**e.** **American Society for Testing and Materials (ASTM)
International,** 100 Barr Harbor Drive, PO Box C700, West Conshohocken,
PA, 19428-2959, or [www.astm.org](http://www.astm.org/).

**f.** Association of European Airlines,
[www.aea.be](http://www.aea.be/).

**CHAPTER 2. SIZING AND SITING DEICING FACILITIES**

**2-1**. **GENERAL.** Aircraft deicing facilities are recommended at
airports where icing conditions are expected. This includes airports
that serve aircraft that can develop frost or ice on critical surfaces
even though the airport itself does not experience ground icing
conditions.

**a. Centralized Deicing Facilities at Terminals.** For some airports,
centralized deicing facilities at or adjacent to terminals can
adequately meet the deicing/anti-icing demands of users and still allow
acceptable taxiing times to the departure runways under varying weather
conditions. Improvements to or expansion of these facilities at terminal
gates should, if practicable, include apron drainage areas that collect
glycol runoff for proper disposal or recycling.

**b. Centralized Deicing Facilities Off the Terminal.** Centralized
deicing facilities off the terminal are recommended when terminal
deicing facilities (including apron facilities) experience excessive
gate delays or taxiing times or suffer from severe weather conditions
conducive to aircraft ground icing conditions. When the construction
cost for runoff mitigation is not cost-effective, terminals with deicing
gates that lack permanent environmental runoff structures are candidates
for off-terminal deicing facilities.

Centralized deicing facilities have the following basic components:

**(1)** aircraft deicing pad(s) for maneuvering aircraft and mobile
deicing vehicles,

**(2)** bypass taxiing capability,

**(3)** environmental runoff mitigation measure,

**(4)** permanent or portable nighttime lighting system, and, but not
necessarily,

**(5)** deicing crew shelter with kitchen and toilet facilities,

**(6)** co-located support facilities that may include one or more of
the following:

**(i)** storage tank(s), transfer system(s) for aircraft
deicing/anti-icing fluid(s),

(ii) fixed-fluid applicator.

**c. Remote Deicing Facilities.** Remote deicing facilities located near
departure runway ends or along taxiways are recommended when taxiing
times from terminals or other centralized deicing facilities frequently
exceed holdover times. Under changing weather conditions, they can
compensate for icing conditions or blowing snow expected to occur along
the taxi route taken by aircraft to the departure runway. These
facilities can improve flow control by permitting retreatment of
aircraft without having the aircraft return to a more distant treatment
site. Remote deicing facilities have the following components:

**(1)** aircraft deicing pad(s) for the maneuvering of aircraft and
mobile deicing vehicles,

**(2)** bypass taxiing capability,

**(3)** environmental runoff mitigation measure, and

**(4)** portable nighttime lighting system.

**2-2. FAA CLEARANCE AND SEPARATION STANDARDS AFFECTING DEICING
FACILITIES.** To ensure aircraft safety, the location and operation of
deicing facilities must follow the clearance and separation standards
specified in AC 150/5300-13, *Airport Design*. These standards involve
airspace, aircraft separations, FAA Technical Operations facilities
critical areas, and Airport Traffic Control Tower (ATCT) line-of-sight
criteria.

**a. Object Clearance Criteria.** Deicing facilities must be sited in
accordance with object clearing criteria described in paragraph 211,
Object Clearing Criteria, in AC 150/5300-13. When constructing deicing
facilities with limited physical space, airports can site the facility
in a non-movement area, i.e., areas not under direct ATCT control. Such
siting reduces wing tip clearance criteria, thereby allowing closer
aircraft separations, i.e., taxilane criteria versus taxiway criteria.
In such cases, the airport operator should contact the ATCT to redefine
a portion of a movement area as non-movement.

**b. FAA Technical Operations.** Deicing facilities must be located so
as not to cause signal interference or signal degradation to existing
FAA radar, navigational aids (NAVAIDs), airport lighting, weather
facilities, communications, etc. This includes interference or
degradation caused by deicing facilities with fluid storage tanks, crew
shelters, and permanent nighttime lighting structures. If any FAA radar,
navigational aid improvements are planned, sufficient obstacle
clearances, as required by new facilities, must be protected. Some
airports may require additional FAA communications equipment to meet the
operational needs of the deicing facility. Additional communications
equipment installations may result from increased ground control
frequencies necessary for the ATCT to provide safe flow of airport
ground traffic and to enable ground deicing personnel to conduct safe
deicing operations. In all cases, the installation of communications
equipment and assignment of frequencies need to be coordinated with FAA
Technical Operations prior to the construction of deicing facilities. To
further protect FAA installations, sites must be evaluated to assess the
impact of jet blast velocities and exhaust deposits.

**c. ATCT Line-of-Sight.** The deicing facility and its supporting
structures must minimize reductions to the ATCT's visual contact with
the movement area. To maintain the ATCT's visual contact, aircraft being
deiced/anti-iced should not obstruct the line-of-sight to active runway
ends and their entrance taxiways. To minimize shadows, aircraft with the
largest surfaces to be treated should be evaluated. Visual contact of
movement areas from planned ATCT cab positions should also be evaluated.

**2-3. CAPACITY OF DEICING FACILITIES.** Airports should have deicing
facilities with a deicing/anti-icing capacity that approximates the
airport's peak hour departure rate that the ATCT can manage during icing
conditions. This departure rate helps determine the number of aircraft
deicing pads required at a facility or facilities to balance the
departure rate and the holdover times of applied deicing/anti-icing
fluids so that, to the extent practicable, holdover times are in effect
when the pilot receives takeoff clearance. To meet the needs of future
aircraft, the FAA recommends an evaluation of aircraft development for a
planning period of at least 10 years. This information is available from
air carriers (e.g., anticipated airline service and aircraft on order)
and airframe manufacturers.

4.  **FACTORS AFFECTING NUMBER OF AIRCRAFT DEICING PADS AND DEICING
    FACILITIES.**

**a.** **Number of Deicing Pads.** Evaluating the impact of the
following factors provides a better estimate of the number of deicing
pads needed at a facility.

**(1) Procedures and Methods of Users.** Facility users will perform
either one-step or two-step deicing/anti-icing procedures. The latter
procedure, routinely used during periods of precipitation, results in
longer occupancy times at deicing pads. To provide users with procedural
flexibility, the number of deicing pads should be based on the two-step
approach. Furthermore, increases to this occupancy time may be needed to
reflect differences in the methods used to treat aircraft and perform
preflight inspections. It is not unusual for users to supplement
preflight inspection items recommended by aircraft manufacturers with
additional items for aircraft having special operational considerations.

**(2) Variations in Meteorological Conditions.** Variations in
meteorological conditions, e.g., type of precipitation, increase the
extent (and frequency) of the deicing/anti-icing treatment. Airports
that commonly experience heavy wet snows or freezing rain should
increase the number of deicing pads to maintain departure flow rates at
levels that avoid unacceptable delays for subsequent aircraft awaiting
treatment. If revised flow control procedures fail to prevent
meteorological conditions from frequently degrading the holdover time
used for the initial treatment, the airport should consider a facility
closer to the active runway. To the extent practicable, there should be
a balance between the number of deicing facilities and their location to
offset severe meteorological conditions so holdover times are in effect
at takeoff.

**(3) Type of Aircraft Receiving Treatment.** The processing time to
deice/anti-ice aircraft for the same weather conditions and fluids
varies by aircraft types. Narrow-body aircraft are processed quicker
than wide-body aircraft, and aircraft with center fuselage mounted
engines, such as DC-10s and Boeing 727s, require additional processing
time. Airports with a high percentage of narrow-body aircraft and a low
percentage of wide-body aircraft may need additional deicing pads to
adequately maintain this particular fleet's departure demand. A balanced
fleet mix may provide a means of increasing a facility's deicing
capacity by relating flow rates of common-sized aircraft to specific
deicing pads.

**(4) Heating Performance and Volume Capacity of Mobile Deicing
Vehicles.** Additional deicing pads may be needed if users operate
mobile deicing vehicles with small tank capacities or vehicles that
require extended periods of time to heat fluids after refilling (that
is, times approaching 20 minutes). Nearby refilling points can help
offset such increases.

**(5) Remote Deicing Facilities.** Depending on the airport,
construction of a remote deicing facility may counter some of the above
factors.

**b. Number of Deicing Facilities.** The estimated number of deicing
pads plus other structural and operational needs of a deicing facility
determine the approximate physical space requirement for siting the
facility. Once the facility's overall physical size requirement is
known, the search for suitable sites follows within the framework of
safety and operational siting factors cited in this AC.

**(1) Multiple Deicing Facilities.** When the estimated number of
deicing pads cannot be physically sited or operationally managed (such
as under usual poor weather conditions) at a single site, the airport
should consider additional facilities.

**(2) Type of Facility User.** Airports serving a wide variety of
scheduled service by regional or commuter air carriers and nonscheduled
service by air taxi, general aviation aircraft, and airline charters may
better meet their deicing/anti-icing needs by constructing a separate
deicing facility for the group. If a single facility is identified for
all airport users, additional physical space may be necessary to meet
the specific needs for one of the groups, e.g., for facilities that
store fluids, adequate space for storing appropriate deicing/anti-icing
fluids for smaller aircraft.

**2-5. FACTORS AFFECTING FACILITY LOCATION AND SIZE.** The primary
factor for siting deicing facilities is the taxiing time that begins
with the start of the last step of the deicing/anti-icing treatment and
ends with takeoff clearance, such that the holdover times of fluids are
still in effect. The analysis should use slower taxiing speeds
experienced under winter-contaminated conditions as well as other
time-contributing factors specific to the airport. SAE ARP 4737 and ISO
11076, *Aircraft -- Ground-based Deicing/Anti-Icing* *Methods with
Fluids,* provide departure planning holdover time charts for various
anti-icers, such as Type I and Type IV, which assist in balancing
holdover times and winter taxiing times from the facility to takeoff.
Other factors involved in locating facilities follow.

**a. Restrictions on Deicing/Anti-icing Fluids.** Restrictions on
deicing fluid usage can impact the siting of facilities. Though used for
the same weather conditions, non-Newtonian fluids, such as Type II and
Type IV, provide longer holdover times than Type I, a Newtonian fluid,
but they are restricted to aircraft with higher takeoff rotational
speeds (e.g., 100 knots or as approved by airframe manufacturers). This
restriction may necessitate siting a facility closer to the departure
runway in order to serve restricted aircraft or to have separate
facilities for the two groups. Also, facility siting may have to take
into account airports that are located in very cold climates since Type
II fluids have a lower temperature application limit, i.e., ‑13° F
(‑25 °C).

**b**. **Effects of Fluid Applicators.**

**(1) Mobile Deicing Vehicles.** Normally, the use of mobile deicing
vehicles as compared to fixed-fluid applicators increases the number of
suitable sites for facilities by permitting closer construction to
active runways. However, for certain airports, a close site may require
construction of new service roads and/or staging areas to allow such
vehicles to serve the facility.

**(2) Fixed-Fluid Applicators.** Use of fixed-fluid applicators, such as
a gantry, telescopic booms, etc., will limit the number of suitable
sites due to height restrictions (see AC 150/5300-13, Object Clearing
Criteria). However, this type of applicator may allow airports to reduce
vehicle traffic and escorting demands or compensate for the lack of
service roads and staging areas. If fixed-fluid applicators are
installed, each deicing pad still must have sufficient outer maneuvering
area for two mobile deicing vehicles.

**c. Fleet Mix.** The physical space required by deicing facilities
depends to some degree on the fleet mix being served. For instance,
airports serving a large variety of aircraft types and sizes may require
facilities more flexible and complex than those airports serving
predominantly one class of aircraft.

**d. Existing Taxiing Routes.** Before siting deicing facilities away
from the terminal areas, an airport should first evaluate the use of
existing taxiways that minimize the taxiing time to the facility and,
more important, the subsequent taxiing time remaining between treatment
and takeoff.

**e. Environmental Runoff Alternative.** The cost-effective
environmental alternatives available to the airport to control deicer
runoff may reduce the number of sites suitable for a deicing facility.
For example, land-locked airports near large bodies of water may have to
site a facility closer to existing sanitary sewers than to departure
runways. It is noted that acceptable alternatives to mitigate deicer
runoff will vary according to city, county, and state environmental
runoff regulations imposed on each airport site.

**f. Integrating Airport Safety Programs.** When identifying
deicing/anti-icing requirements, the airport should look for ways of
integrating current airport safety programs with the operation of the
deicing facility, thereby continuing airport safety initiatives. For
instance, the runway incursion program at busy airports may be
maintained by widening service roads for bi-directional traffic or by
designating additional staging areas instead of constructing separate
roads. Other potentially affected safety programs include the airport's
Surface Movement Guidance and Control System (SMGCS), Emergency Plan and
the Snow and Ice Control Plan. More than likely, there will be changes
to the last plan. For instance, the airport may need to reclassify
previously non-cleared service roads to departure runways that will be
needed by deicing vehicles or authorized personnel for post-treatment
exterior checks to priority 1 snow clearing status.

**2-6. FLUID HANDLING REQUIREMENTS AT DEICING FACILITIES.**

**a. Storage Tank and Fluid Transfer System Designs.** Overheating,
excessive mechanical shearing, or contamination, e.g., from corroded
tanks, may degrade the holdover characteristics of non-Newtonian fluids.
Non-Newtonian fluids are Type II, Type III, and Type IV. Newtonian
fluids are Type I (see SAE ARP 4737, for fluid classifications). To
protect the performance characteristics of these fluids from
degradation, storage tanks and fluid transfer systems installed at
deicing facilities must be designed in accordance with the fluid
manufacturer's recommendations. Fluid transfer systems must be dedicated
to the specific fluid being handled to prevent the inadvertent mixing of
fluids of different types or different manufactures. Fluid manufacturers
should provide the airport manager recommendations about compatible
pumps, control valves, piping, and compatible storage tanks.
Additionally, SAE ARP 4737 provides industry recommended practices for
storage tank and transfer systems.

**b. Separate Storage Tank Capacity.** Deicing facilities using various
types of deicing/anti-icing fluids will require more physical space to
permit separate storage of fluids. Fluid manufacturers should always be
consulted for storage tank requirements, maintenance, and precautions
for currently used fluids and new products entering the market.

**c. Tanks, Fill Ports, and Discharge Points Labeling.** To avoid
cross-contamination of deicing fluids at a deicing facility, all tanks,
fill ports, and discharge points must be conspicuously labeled for the
type of fluid handled, e.g., *SAE TYPE I AIRCRAFT DEICING FLUID, ISO
TYPE II AIRCRAFT DEICING FLUID*.

**2-7. NIGHTTIME LIGHTING.** All facilities will provide permanent
nighttime lighting structures or have portable nighttime lighting
systems available so ground crews have the necessary illumination for
deicing/anti-icing operations and pre-takeoff inspections during night
or low-visibility conditions. One portable alternative is mobile deicing
vehicles with modified lights that provide sufficient illumination for
deicing/anti-icing treatments and pre-takeoff inspections during night
or low visibility. AC 150/5360-13, *Planning and Design Guidelines for
Airport Terminal Facilities,* table 4-1, provides general lighting
requirements for apron-related functions. The height of lighting poles
must be in accordance with AC 150/5300-13 Object Clearing Criteria.
Permanent nighttime lights should be aimed and shielded to avoid glare
to pilots and the ATCT's line-of-sight without reducing the illumination
of critical areas.

**2-8. BYPASS TAXIING CAPABILITY.** To further maximize departure flows
for all departing aircraft, potential sites should have enough physical
space to allow bypass taxiing capability for aircraft not needing
treatment. This feature permits the facility to receive aircraft that
require treatment, while allowing other aircraft to continue unimpeded
for departure. Figure 2-1 provides an example.

**2-9. MULTIPLE DEICING QUEUES.** Gains in deicing capacity at off-gate
facilities are possible when deicing pads have individual entrance and
exit queuing capabilities (for example, see figures 3-2, 3-3, and 3-4).
These features give the ATCT greater flexibility to issue departure
clearances without subjecting aircraft to a "first-in/first-out" queuing
situation. Such design features are recommended, if practicable, for
off-gate facilities that experience extended periods of operation under
continuous poor weather conditions.

**2-10. TOPOGRAPHY.** Topography is a key cost factor in constructing a
deicing facility.

**a. Final Grades.** To reduce construction costs, facilities should be
sited on relatively flat land where the natural terrain features conform
to the final grades for the ultimate design of the deicing facility.

**b. Drainage Areas.** Sites with high water tables that require costly
subdrainage and a runoff mitigation alternative should be avoided. The
final site should readily lend itself to facility runoff mitigation at
reasonable cost. AC 150/5320-5, *Surface Drainage Design,* provides
design standards for airfield drainage systems.

**2-11. UTILITIES.** Although utility considerations are subordinate to
other siting factors, the airport manager should evaluate whether to
extend electric power, telephone service and sanitary or storm sewers to
support an off-gate facility. For some situations, independent service
installations or a separate runoff mitigation alternative at the site
may be more cost-effective.

**2-12. THE AIRPORT LAYOUT PLAN (ALP) AND SITING AND SIZING
FACILITIES.** Review of the airport's ALP provides information that
should simplify the siting and sizing process. Some ALPs delineate
planned land acquisition areas adjacent to airport property for airport
development. Consequently, a revision can show areas identified for a
deicing facility. Any changes to the ALP should be considered carefully
and all changes documented and submitted to the FAA for approval.

![](media/image5.png){width="4.46875in" height="3.5104166666666665in"}

## Figure 2-1. Separate taxiing entrance to an aircraft deicing facility

# This page intentionally blank.

#  

**CHAPTER 3. DESIGN OF AIRCRAFT DEICING PADS**

**3-1. AIRCRAFT DEICING PADS.** The size of an aircraft deicing pad is
determined by the aircraft parking area and the maneuvering area for
mobile deicing vehicles as shown in figure 1-1.

**a. Aircraft Parking Area.** This area is the inner area used for
parking aircraft to receive deicing/anti-icing treatment.

**(1) Width.** The width of the parking area equals the upper wingspan
of the most demanding airplane design group (ADG) using the deicing pad.

**(2) Length.** The length of the parking area equals the fuselage
length of the most demanding aircraft using the deicing pad.

**b. Maneuvering Area for Mobile Deicing Vehicles.** This outer area
provides the "vehicle lane width" necessary for two or more mobile
deicing vehicles to satisfactorily perform simultaneous and complete
left- and right-side uniform fluid distribution techniques for removing
deposits of frost, ice, slush, and snow from aircraft surfaces and for
anti-icing operations. The vehicle lane width must be 12.5 feet (3.8 m)
and be mutually exclusive of any adjacent deicing pad. As noted by SAE
ARP 4737, *"Dual vehicle fluid applications help in eliminating
potential aerodynamic problems resulting from fluid applications by a
single mobile deicing vehicle."*

**3-2. SEPARATION STANDARDS FOR OFF-GATE AIRCRAFT DEICING PADS.**
Aircraft deicing pads for off-gate facilities will have parallel taxiway
centerlines. Separation criteria provided in table 3-1 takes into
account the need for individual deicing pads to provide sufficient
maneuvering area around the aircraft to allow simultaneous treatment by
two or more mobile deicing vehicles (see paragraph 1-2(d)(2) and figure
1-1) and, with the exception of column #5 of table 3-1, sufficient
non-overlapping space for a vehicle safety zone (VSZ) between adjacent
deicing pads (see paragraph 3-4(d)) and for outer deicing pads. Thus a
permanent deicing facility with three deicing pads will have six
vehicles maneuvering areas (VMAs) and four VSZs. Table 3-1 observes
taxiway centerline to fixed or movable object criteria because VSZs
house fixed and movable objects. Furthermore, table 3-1 entries and
footnotes ensure that sufficient separation exists between taxi
centerlines and VSZs for VMAs. Table 3-1 offers airport operators the
option to locate permanent off-gate deicing facilities in the movement
or non-movement areas. Column #5, off-gate deicing facilities without
vehicle safety zones, reflects the practice by airport operators to
designate on a temporary basis the use of suitable apron areas, near a
departure runway or adjacent to terminal gates, for deicing/anti-icing
airplanes. Temporary off-gate deicing facilities may have vehicle safety
zones, but they generally lack the infrastructure that is associated
with permanent off-gate deicing facilities, such as a snow control
center with a crew shelter, overhead lighting, and possibly electronic
message boards.

**3-3. FIXED-FLUID APPLICATORS.** Fixed-fluid applicators should
satisfactorily perform simultaneous and complete left- and right-side
uniform fluid distribution techniques for removing deposits of frost,
ice, slush, and snow from aircraft surfaces and for anti-icing
operations. Fixed-fluid applicators, such as gantries or telescopic
booms, can have the advantage of reducing vehicle traffic and lowering
the quantities of fluid used. Though fixed-fluid applicators may be the
primary deicing applicators for a deicing pad, the pad must have enough
maneuvering area for mobile deicing vehicles to provide secondary backup
capabilities in case of primary equipment failures.

**3-4.** **PAVEMENT SURFACE MARKINGS FOR OFF-GATE DEICING FACILITIES.**

**a.** **Taxiway Centerline Surface Markings.** Off-gate deicing
facilities will have taxiway centerline surface markings for entering a
deicing pad, moving through the deicing pad, and exiting the facility.
The surface marking must be in accordance with AC 150/5340-1, *Standards
for Airport Markings.* At airports operating below 1,200 feet runway
visual range (RVR), deicing facilities located on a designated SMGCS
low-visibility taxi route (see AC 120-57, *Surface Movement Guidance and
Control System (SMGCS))* may require additional taxiing route surface
marking, lighting, and sign systems necessary to support SMGCS
operations.

**b.** **Facility Boundary Surface Marking.** Off-gate deicing
facilities must have a taxiway/taxiway holding position surface marking
to indicate the entrance and exit boundary of the facility (figure 2-1).
The surface marking, which serves two functions, must be in accordance
with paragraph 3-4(b)(1) and (b)(2). This marking reduces incursions by
deicing crews and aircraft into the object free area of the connecting
taxiway during nighttime or low-visibility conditions. Also, it
identifies the ground control transfer points between the ATCT and
facility control. Lighted signage may be used instead of surface
markings only at the facility entrance. If lighted signs are used, they
must be in accordance with AC 150/5340-18, *Standards for Airport Sign
Systems*.

**(1) Surface Marking.** The taxiway/taxiway holding position surface
marking (perimeter of the facility) must be marked in accordance with AC
150/5340-1 (see figure 3-1(a)).

+------+-----------+-----------+-----------+-----------+------------+
| *A   | *Off-Gate |           |           |           |            |
| irpl | Aircraft  |           |           |           |            |
| ane* | Deicing   |           |           |           |            |
|      | Fa        |           |           |           |            |
| *Des | cilities* |           |           |           |            |
| ign* |           |           |           |           |            |
|      |           |           |           |           |            |
| *G   |           |           |           |           |            |
| roup |           |           |           |           |            |
| **^2 |           |           |           |           |            |
| ^*** |           |           |           |           |            |
|      |           |           |           |           |            |
| *(A  |           |           |           |           |            |
| DG)* |           |           |           |           |            |
+------+-----------+-----------+-----------+-----------+------------+
|      | *Non      |           | *Movement |           |            |
|      | -Movement |           | Are       |           |            |
|      | Are       |           | a**^1^*** |           |            |
|      | a**^1^*** |           |           |           |            |
+------+-----------+-----------+-----------+-----------+------------+
|      | *Column   | *Column   | *Column   | *Column   | *Column #5 |
|      | #         | #         | #         | #         | **^4^***   |
|      | 1**^3^*** | 2**^3^*** | 3**^3^*** | 4**^3^*** |            |
|      |           |           |           |           | *Temporary |
|      | *Outer    | *Interior | *Outer    | *Interior | Deicing    |
|      | Deicing   | Deicing   | Deicing   | Deicing   | Pads*      |
|      | Pad*      | Pads*     | Pad*      | Pads*     |            |
|      |           |           |           |           | *Taxi CL   |
|      | *Taxi     | *Taxi CL  | *Taxi CL  | *Taxi CL  | to*        |
|      | C         | to*       | to*       | to*       |            |
|      | enterline |           |           |           | *Taxi CL*  |
|      | (CL) to   | *Taxi CL* | *Edge of  | *Taxi CL* |            |
|      | Edge of   |           | VSZ*      |           |            |
|      | Vehicle   |           |           |           |            |
|      | Safety    |           |           |           |            |
|      | Zone      |           |           |           |            |
|      | (VSZ)*    |           |           |           |            |
+------+-----------+-----------+-----------+-----------+------------+
|      | *         | *         | *         | *         | *Includes* |
|      | Includes* | Includes* | Includes* | Includes* |            |
|      |           |           |           |           | *VMAs and  |
|      | *1        | *2 VMAs + | *1 VMA*   | *2 VMAs + | no VSZ*    |
|      | Vehicle   | 1 VSZ*    |           | 1 VSZ*    |            |
|      | Ma        |           |           |           |            |
|      | neuvering |           |           |           |            |
|      | Area      |           |           |           |            |
|      | (VMA)*    |           |           |           |            |
+------+-----------+-----------+-----------+-----------+------------+
| *ADG | *167 ft*  | *344 ft*  | *193 ft*  | *396 ft*  | *324 ft*   |
| VI*  |           |           |           |           |            |
|      | *(51 m)*  | *(105 m)* | *(59 m)*  | *(120.5   | *(99 m)*   |
|      |           |           |           | m)*       |            |
+------+-----------+-----------+-----------+-----------+------------+
| *ADG | *138 ft*  | *286 ft*  | *160 ft*  | *330 ft*  | *267 ft*   |
| V*   |           |           |           |           |            |
|      | *(42 m)*  | *(87 m)*  | *(48.5    | *(100.5)* | *(81 m)*   |
|      |           |           | m)*       |           |            |
+------+-----------+-----------+-----------+-----------+------------+
| *ADG | *112.5    | *235 ft*  | *129.5    | *269 ft*  | *215 ft*   |
| IV*  | ft*       |           | ft*       |           |            |
|      |           | *(71.5    |           | *(82 m)*  | *(65.5 m)* |
|      | *(34 m)*  | m)*       | *(39.5    |           |            |
|      |           |           | m)*       |           |            |
+------+-----------+-----------+-----------+-----------+------------+
| *ADG | *81 ft*   | *172 ft*  | *93 ft*   | *196 ft*  | *152 ft*   |
| III* |           |           |           |           |            |
|      | *(24.5    | *(52.5    | *(28.5    | *(59.5    | *(46.5 m)* |
|      | m)*       | m)*       | m)*       | m)*       |            |
+------+-----------+-----------+-----------+-----------+------------+
| *ADG | *57.5 ft* | *125 ft*  | *65.5 ft* | *141 ft*  | *105 ft*   |
| II*  |           |           |           |           |            |
|      | *(17.5    | *(38 m)*  | *(20 m)*  | *(43 m)*  | *(32 m)*   |
|      | m)*       |           |           |           |            |
+------+-----------+-----------+-----------+-----------+------------+
| *ADG | *39.5 ft* | *89 ft*   | *44.5 ft* | *99 ft*   | *74 ft*    |
| I*   |           |           |           |           |            |
|      | *(12 m)*  | *(27 m)*  | *(13.5    | *(30 m)*  | *(22.5 m)* |
|      |           |           | m)*       |           |            |
+------+-----------+-----------+-----------+-----------+------------+
| The  |           |           |           |           |            |
| va   |           |           |           |           |            |
| lues |           |           |           |           |            |
| obta |           |           |           |           |            |
| ined |           |           |           |           |            |
| from |           |           |           |           |            |
| the  |           |           |           |           |            |
| f    |           |           |           |           |            |
| ollo |           |           |           |           |            |
| wing |           |           |           |           |            |
| e    |           |           |           |           |            |
| quat |           |           |           |           |            |
| ions |           |           |           |           |            |
| may  |           |           |           |           |            |
| be   |           |           |           |           |            |
| used |           |           |           |           |            |
| to   |           |           |           |           |            |
| show |           |           |           |           |            |
| that |           |           |           |           |            |
| a    |           |           |           |           |            |
| modi |           |           |           |           |            |
| fica |           |           |           |           |            |
| tion |           |           |           |           |            |
| of   |           |           |           |           |            |
| stan |           |           |           |           |            |
| dard |           |           |           |           |            |
| will |           |           |           |           |            |
| pro  |           |           |           |           |            |
| vide |           |           |           |           |            |
| an   |           |           |           |           |            |
| ac   |           |           |           |           |            |
| cept |           |           |           |           |            |
| able |           |           |           |           |            |
| l    |           |           |           |           |            |
| evel |           |           |           |           |            |
| of   |           |           |           |           |            |
| saf  |           |           |           |           |            |
| ety. |           |           |           |           |            |
| R    |           |           |           |           |            |
| efer |           |           |           |           |            |
| to   |           |           |           |           |            |
| p    |           |           |           |           |            |
| arag |           |           |           |           |            |
| raph |           |           |           |           |            |
| 6 of |           |           |           |           |            |
| AC   |           |           |           |           |            |
| 150  |           |           |           |           |            |
| /530 |           |           |           |           |            |
| 0-13 |           |           |           |           |            |
| for  |           |           |           |           |            |
| guid |           |           |           |           |            |
| ance |           |           |           |           |            |
| on   |           |           |           |           |            |
| modi |           |           |           |           |            |
| fica |           |           |           |           |            |
| tion |           |           |           |           |            |
| of   |           |           |           |           |            |
| stan |           |           |           |           |            |
| dard |           |           |           |           |            |
| r    |           |           |           |           |            |
| equi |           |           |           |           |            |
| reme |           |           |           |           |            |
| nts. |           |           |           |           |            |
|      |           |           |           |           |            |
| Co   |           |           |           |           |            |
| lumn |           |           |           |           |            |
| No.  |           |           |           |           |            |
| 1:   |           |           |           |           |            |
| Taxi |           |           |           |           |            |
| lane |           |           |           |           |            |
| CL   |           |           |           |           |            |
| to   |           |           |           |           |            |
| f    |           |           |           |           |            |
| ixed |           |           |           |           |            |
| or   |           |           |           |           |            |
| mov  |           |           |           |           |            |
| able |           |           |           |           |            |
| ob   |           |           |           |           |            |
| ject |           |           |           |           |            |
| eq   |           |           |           |           |            |
| uals |           |           |           |           |            |
| 0.6  |           |           |           |           |            |
| t    |           |           |           |           |            |
| imes |           |           |           |           |            |
| airp |           |           |           |           |            |
| lane |           |           |           |           |            |
| wing |           |           |           |           |            |
| span |           |           |           |           |            |
| (WS) |           |           |           |           |            |
| plus |           |           |           |           |            |
| 10   |           |           |           |           |            |
| fe   |           |           |           |           |            |
| et - |           |           |           |           |            |
| \    |           |           |           |           |            |
| [(0. |           |           |           |           |            |
| 6)(W |           |           |           |           |            |
| S) + |           |           |           |           |            |
| 10\] |           |           |           |           |            |
| for  |           |           |           |           |            |
| all  |           |           |           |           |            |
| A    |           |           |           |           |            |
| DGs. |           |           |           |           |            |
|      |           |           |           |           |            |
| Co   |           |           |           |           |            |
| lumn |           |           |           |           |            |
| No.  |           |           |           |           |            |
| 2:   |           |           |           |           |            |
| Taxi |           |           |           |           |            |
| lane |           |           |           |           |            |
| CL   |           |           |           |           |            |
| to   |           |           |           |           |            |
| para |           |           |           |           |            |
| llel |           |           |           |           |            |
| taxi |           |           |           |           |            |
| lane |           |           |           |           |            |
| CL   |           |           |           |           |            |
| with |           |           |           |           |            |
| f    |           |           |           |           |            |
| ixed |           |           |           |           |            |
| or   |           |           |           |           |            |
| mov  |           |           |           |           |            |
| able |           |           |           |           |            |
| ob   |           |           |           |           |            |
| ject |           |           |           |           |            |
| eq   |           |           |           |           |            |
| uals |           |           |           |           |            |
| \    |           |           |           |           |            |
| [(1. |           |           |           |           |            |
| 2)(W |           |           |           |           |            |
| S) + |           |           |           |           |            |
| 30\] |           |           |           |           |            |
| for  |           |           |           |           |            |
| all  |           |           |           |           |            |
| A    |           |           |           |           |            |
| DGs, |           |           |           |           |            |
| plus |           |           |           |           |            |
| with |           |           |           |           |            |
| ADG  |           |           |           |           |            |
| I,   |           |           |           |           |            |
| w    |           |           |           |           |            |
| ings |           |           |           |           |            |
| pans |           |           |           |           |            |
| less |           |           |           |           |            |
| than |           |           |           |           |            |
| 25   |           |           |           |           |            |
| feet |           |           |           |           |            |
| req  |           |           |           |           |            |
| uire |           |           |           |           |            |
| su   |           |           |           |           |            |
| ffic |           |           |           |           |            |
| ient |           |           |           |           |            |
| se   |           |           |           |           |            |
| para |           |           |           |           |            |
| tion |           |           |           |           |            |
| for  |           |           |           |           |            |
| two  |           |           |           |           |            |
| VMAs |           |           |           |           |            |
| and  |           |           |           |           |            |
| one  |           |           |           |           |            |
| VSZ. |           |           |           |           |            |
|      |           |           |           |           |            |
| Co   |           |           |           |           |            |
| lumn |           |           |           |           |            |
| No.  |           |           |           |           |            |
| 3:   |           |           |           |           |            |
| Tax  |           |           |           |           |            |
| iway |           |           |           |           |            |
| CL   |           |           |           |           |            |
| to   |           |           |           |           |            |
| f    |           |           |           |           |            |
| ixed |           |           |           |           |            |
| or   |           |           |           |           |            |
| mov  |           |           |           |           |            |
| able |           |           |           |           |            |
| ob   |           |           |           |           |            |
| ject |           |           |           |           |            |
| eq   |           |           |           |           |            |
| uals |           |           |           |           |            |
| \    |           |           |           |           |            |
| [(0. |           |           |           |           |            |
| 7)(W |           |           |           |           |            |
| S) + |           |           |           |           |            |
| 10\] |           |           |           |           |            |
| for  |           |           |           |           |            |
| all  |           |           |           |           |            |
| A    |           |           |           |           |            |
| DGs. |           |           |           |           |            |
|      |           |           |           |           |            |
| Co   |           |           |           |           |            |
| lumn |           |           |           |           |            |
| No.  |           |           |           |           |            |
| 4:   |           |           |           |           |            |
| Tax  |           |           |           |           |            |
| iway |           |           |           |           |            |
| CL   |           |           |           |           |            |
| to   |           |           |           |           |            |
| para |           |           |           |           |            |
| llel |           |           |           |           |            |
| tax  |           |           |           |           |            |
| iway |           |           |           |           |            |
| CL   |           |           |           |           |            |
| with |           |           |           |           |            |
| f    |           |           |           |           |            |
| ixed |           |           |           |           |            |
| or   |           |           |           |           |            |
| mov  |           |           |           |           |            |
| able |           |           |           |           |            |
| ob   |           |           |           |           |            |
| ject |           |           |           |           |            |
| eq   |           |           |           |           |            |
| uals |           |           |           |           |            |
| \    |           |           |           |           |            |
| [(1. |           |           |           |           |            |
| 4)(W |           |           |           |           |            |
| S) + |           |           |           |           |            |
| 30\] |           |           |           |           |            |
| for  |           |           |           |           |            |
| all  |           |           |           |           |            |
| A    |           |           |           |           |            |
| DGs, |           |           |           |           |            |
| plus |           |           |           |           |            |
| with |           |           |           |           |            |
| ADG  |           |           |           |           |            |
| I,   |           |           |           |           |            |
| w    |           |           |           |           |            |
| ings |           |           |           |           |            |
| pans |           |           |           |           |            |
| less |           |           |           |           |            |
| than |           |           |           |           |            |
| 15   |           |           |           |           |            |
| feet |           |           |           |           |            |
| req  |           |           |           |           |            |
| uire |           |           |           |           |            |
| su   |           |           |           |           |            |
| ffic |           |           |           |           |            |
| ient |           |           |           |           |            |
| se   |           |           |           |           |            |
| para |           |           |           |           |            |
| tion |           |           |           |           |            |
| for  |           |           |           |           |            |
| two  |           |           |           |           |            |
| VMAs |           |           |           |           |            |
| and  |           |           |           |           |            |
| one  |           |           |           |           |            |
| VSZ. |           |           |           |           |            |
|      |           |           |           |           |            |
| Co   |           |           |           |           |            |
| lumn |           |           |           |           |            |
| No.  |           |           |           |           |            |
| 5:   |           |           |           |           |            |
| Tax  |           |           |           |           |            |
| iway |           |           |           |           |            |
| CL   |           |           |           |           |            |
| to   |           |           |           |           |            |
| para |           |           |           |           |            |
| llel |           |           |           |           |            |
| tax  |           |           |           |           |            |
| iway |           |           |           |           |            |
| CL   |           |           |           |           |            |
| eq   |           |           |           |           |            |
| uals |           |           |           |           |            |
| \    |           |           |           |           |            |
| [(1. |           |           |           |           |            |
| 2)(W |           |           |           |           |            |
| S) + |           |           |           |           |            |
| 10\] |           |           |           |           |            |
| for  |           |           |           |           |            |
| ADGs |           |           |           |           |            |
| III  |           |           |           |           |            |
| --   |           |           |           |           |            |
| VI.  |           |           |           |           |            |
| A    |           |           |           |           |            |
| pply |           |           |           |           |            |
| the  |           |           |           |           |            |
| same |           |           |           |           |            |
| equa |           |           |           |           |            |
| tion |           |           |           |           |            |
| for  |           |           |           |           |            |
| ADGs |           |           |           |           |            |
| I    |           |           |           |           |            |
| and  |           |           |           |           |            |
| II,  |           |           |           |           |            |
| but  |           |           |           |           |            |
| w    |           |           |           |           |            |
| ings |           |           |           |           |            |
| pans |           |           |           |           |            |
| less |           |           |           |           |            |
| than |           |           |           |           |            |
| 75   |           |           |           |           |            |
| feet |           |           |           |           |            |
| req  |           |           |           |           |            |
| uire |           |           |           |           |            |
| su   |           |           |           |           |            |
| ffic |           |           |           |           |            |
| ient |           |           |           |           |            |
| se   |           |           |           |           |            |
| para |           |           |           |           |            |
| tion |           |           |           |           |            |
| for  |           |           |           |           |            |
| two  |           |           |           |           |            |
| VMAs |           |           |           |           |            |
| and  |           |           |           |           |            |
| no   |           |           |           |           |            |
| VSZ. |           |           |           |           |            |
+------+-----------+-----------+-----------+-----------+------------+
| Note |           |           |           |           |            |
| 1:   |           |           |           |           |            |
| Fa   |           |           |           |           |            |
| cili |           |           |           |           |            |
| ties |           |           |           |           |            |
| b    |           |           |           |           |            |
| uilt |           |           |           |           |            |
| in   |           |           |           |           |            |
| non- |           |           |           |           |            |
| move |           |           |           |           |            |
| ment |           |           |           |           |            |
| a    |           |           |           |           |            |
| reas |           |           |           |           |            |
| are  |           |           |           |           |            |
| not  |           |           |           |           |            |
| u    |           |           |           |           |            |
| nder |           |           |           |           |            |
| di   |           |           |           |           |            |
| rect |           |           |           |           |            |
| ATCT |           |           |           |           |            |
| cont |           |           |           |           |            |
| rol. |           |           |           |           |            |
| Fa   |           |           |           |           |            |
| cili |           |           |           |           |            |
| ties |           |           |           |           |            |
| b    |           |           |           |           |            |
| uilt |           |           |           |           |            |
| in   |           |           |           |           |            |
| move |           |           |           |           |            |
| ment |           |           |           |           |            |
| a    |           |           |           |           |            |
| reas |           |           |           |           |            |
| are  |           |           |           |           |            |
| u    |           |           |           |           |            |
| nder |           |           |           |           |            |
| di   |           |           |           |           |            |
| rect |           |           |           |           |            |
| ATCT |           |           |           |           |            |
| cont |           |           |           |           |            |
| rol. |           |           |           |           |            |
|      |           |           |           |           |            |
| Note |           |           |           |           |            |
| 2:   |           |           |           |           |            |
| ADGs |           |           |           |           |            |
| are  |           |           |           |           |            |
| def  |           |           |           |           |            |
| ined |           |           |           |           |            |
| in   |           |           |           |           |            |
| AC   |           |           |           |           |            |
| 150/ |           |           |           |           |            |
| 5300 |           |           |           |           |            |
| -13, |           |           |           |           |            |
| p    |           |           |           |           |            |
| arag |           |           |           |           |            |
| raph |           |           |           |           |            |
| 2.   |           |           |           |           |            |
| T    |           |           |           |           |            |
| able |           |           |           |           |            |
| 3-1  |           |           |           |           |            |
| va   |           |           |           |           |            |
| lues |           |           |           |           |            |
| as   |           |           |           |           |            |
| sume |           |           |           |           |            |
| lar  |           |           |           |           |            |
| gest |           |           |           |           |            |
| airp |           |           |           |           |            |
| lane |           |           |           |           |            |
| wing |           |           |           |           |            |
| span |           |           |           |           |            |
| wi   |           |           |           |           |            |
| thin |           |           |           |           |            |
| each |           |           |           |           |            |
| ADG. |           |           |           |           |            |
|      |           |           |           |           |            |
| Note |           |           |           |           |            |
| 3:   |           |           |           |           |            |
| Col  |           |           |           |           |            |
| umns |           |           |           |           |            |
| #1   |           |           |           |           |            |
| -- 4 |           |           |           |           |            |
| have |           |           |           |           |            |
| a    |           |           |           |           |            |
| 1    |           |           |           |           |            |
| 2.5- |           |           |           |           |            |
| foot |           |           |           |           |            |
| (3.  |           |           |           |           |            |
| 8-m) |           |           |           |           |            |
| wide |           |           |           |           |            |
| VMAs |           |           |           |           |            |
| and  |           |           |           |           |            |
| a    |           |           |           |           |            |
| 10-  |           |           |           |           |            |
| foot |           |           |           |           |            |
| (    |           |           |           |           |            |
| 3-m) |           |           |           |           |            |
| wide |           |           |           |           |            |
| VSZ. |           |           |           |           |            |
|      |           |           |           |           |            |
| Note |           |           |           |           |            |
| 4:   |           |           |           |           |            |
| Co   |           |           |           |           |            |
| lumn |           |           |           |           |            |
| #5   |           |           |           |           |            |
| has  |           |           |           |           |            |
| 1    |           |           |           |           |            |
| 2.5- |           |           |           |           |            |
| foot |           |           |           |           |            |
| (3.  |           |           |           |           |            |
| 8-m) |           |           |           |           |            |
| wide |           |           |           |           |            |
| VMA  |           |           |           |           |            |
| and  |           |           |           |           |            |
| no   |           |           |           |           |            |
| VSZ. |           |           |           |           |            |
+------+-----------+-----------+-----------+-----------+------------+

**Table 3-1. Separation criteria for off-gate aircraft deicing pads
having parallel taxiways**

**(2) Location.** The taxiway/ taxiway holding position marking will be
located outside all taxiway/taxilane object free areas (OFAs), runway
safety areas, runway obstacle free zones (OFZs), and FAA Technical
Operations facility critical areas, e.g., navigation aids (NAVAIDS).

**c. Deicing Pad Identification Surface Marking.** Off-gate deicing
facilities must have the entrance of each deicing pad marked with a
deicing pad identification surface marking to assist pilots in
identifying the assigned deicing pad. The surface marking is rectangular
in shape with alphanumeric inscriptions in accordance with paragraph
28*, Surface Painted Taxiway Location Signs,* of AC 150/5340-1, with the
exception that the rectangle will be symmetrically located on the
facility's entrance taxiway centerline as shown in figure 3-1(b). The
location should also facilitate the pilot's line-of-sight from both
directions.

**(1) Dual-Sided Operations.** Facilities that operate with aircraft
entering from either end of the facility must provide a deicing pad
identification surface marking at each entrance to the deicing pad with
the identifiers facing the pilot.

**(2) Composite Deicing Pad Surface Markings.** If a single deicing pad
will serve as a composite deicing pad (or "grouping") such as pad #5 in
figure 3-3, which incorporates pads #4 and #6, then a single entrance
taxiway centerline surface marking will be used for the grouping*.*
After a given distance, the single entrance centerline will separate
into individual taxiway centerlines for the incorporated deicing pads.
Each individual taxiway centerline entrance within the grouping will be
marked with its own deicing pad identifier. Since these pads are used as
a grouping, the deicing pad identifiers will use the same alpha
character followed by a different numeric character. For example, the
pad grouping #4, #5, and #6 would be identified as D2, D1, and D3,
respectively, with the main entrance taxiway centerline serving pad #5
designated as D1.

**d. Vehicle Safety Zone Surface Markings.** Each deicing pad at
off-gate deicing facilities must have a vehicle safety zone (VSZ)
surface marking on each side of its taxiway centerline in accordance
with figure 3-1(c). The VSZ functions as a safety zone for personnel and
parked deicing vehicles and other equipment before and after
deicing/anti-icing operations. For a composite deicing pad (grouping),
such as pads #4, #5, #6 in figure 3-3, two VSZs are provided for the
grouping, one VSZ to the left of pad #4 and the other VSZ to the right
of pad #6.

**(1) Width of VSZs.** The minimum width for the VSZ is 10 feet (3.0 m),
which restricts vehicle parking to "face-to-face" instead of
"side-by-side".

**(2)** **Overall Length of VSZs.** The overall continuous length of the
VSZ should offer "trouble-free" parking of the vehicle fleet required to
perform the deicing/anti-icing operations. In all cases, the overall
continuous length will be such that neither end of the VSZ violates the
taxiway/taxilane object free area of taxiways or taxilanes located
outside the boundary of the deicing facility. Depending on the jet blast
profiles of certain aircraft, the length of the VSZ toward the exit side
of the facility may need to be reduced to minimize severe jet blast
impacts onto parked vehicles and personnel when the aircraft exits and
turns onto the connecting taxiway.

**(3) Location of VSZs.** Case 1 -- Placement of VSZs between adjacent
deicing pads will be in accordance with paragraph 3-2 of this AC. Case 2
-- Placement of the VSZ on the outermost deicing pad will be in
accordance with fixed/movable criteria specified in table 2-3 in AC
150/5300-13.

**3-5. DEICING PAD LAYOUTS.** Layouts for deicing pads should maximize
the flexibility of deicing operations and reduce ATCT workloads. The
following layouts provide alternatives for varying weather conditions.

**a. Layouts.**

**(1) Common Deicing Pad Layout.** A common deicing pad layout has a
single centerline through the deicing pad to guide all sized aircraft.
For facilities serving a fleet mix with numerous wide-body aircraft,
separating deicing pads for wide-body aircraft from other aircraft may
increase deicing capacity (see pad #1 in figure 3-2).

**(2) Composite Deicing Pad Layout.** A composite deicing pad layout has
more than one centerline through the deicing pad to guide different
sized aircraft. For facilities serving a balanced mix of different sized
aircraft, correlating the percentages of aircraft types to their
departure rates may increase deicing capacity (see figure 3-3). When two
aircraft use a common centerline, additional parking space between
aircraft may be needed to account for exiting jet blast degradation of
Type II protective coatings and velocities on personnel/equipment (see
paragraph 3-5c(1)).

![](media/image6.png){width="3.407638888888889in"
height="3.2597222222222224in"}

**Figure 3-1(a). Facility taxiway/taxiway holding position marking**

![](media/image7.png){width="6.563888888888889in"
height="3.7916666666666665in"}

**Figure 3-1(b). Deicing pad identification ("B5") surface marking at
entrance point**

**b. Centerline Orientation.**

**(1) Frequent High Wind Velocities.** Airports that experience frequent
high wind velocities should, to the extent practicable, orient the
centerlines of deicing pads with the prevailing wind. This allows heated
fluids to be applied closer to the surface of the aircraft skin, thereby
minimizing heat loss and fluid usage, and takes advantage of the full
hydraulic force of the fluid spray. The AEA notes under deicing
application procedures, *"For maximum effect, fluids shall be applied
close to the aircraft surfaces to minimize heat loss."*

**(2) Low Visibility.** From a winter operational standpoint, low
visibility, etc., maintaining the cockpit over centerline reduces the
possibility of

excursions from the facility's taxiways compared to judgmental
oversteering. AC 150/5300-13 provides the criteria for ample curve and
fillet radii necessary for cockpit-over-centerline taxiing.

**(3) Minimizing Facility Depths.** Additional suitable sites for
airports may be possible by orienting the centerlines of deicing pads so
they are non-perpendicular to the connecting taxiway. Figure 3-4
illustrates centerlines oriented 45 degrees to the connecting taxiway.
In this case, the facility's depths serving MD-80s (L=147.8 ft (45.0 m))
and Boeing 737-400s (L=119.6 ft (36.5 m)) would be reduced approximately
43 feet (13 m) and 35 feet (10.6 m), respectively a 30-percent depth
reduction. (L is the fuselage length.)

![](media/image8.png){width="3.533333333333333in"
height="4.944444444444445in"}

**Figure 3-1(c). Vehicle safety zone surface marking standards**

![](media/image9.png){width="4.902777777777778in" height="2.46875in"}

**Figure 3-2. Example of a common deicing pad layout**

![](media/image10.png){width="5.210416666666666in"
height="2.5527777777777776in"}

**Figure 3-3. Example of a composite deicing pad layout**

![](media/image11.png){width="5.4430555555555555in"
height="2.759027777777778in"}

**Figure 3-4. Deicing pad centerlines oriented 45 degrees to the
connecting taxiway**

**c. Exiting Jet Blast.**

**(1) Exiting Aircraft.** The deicing pad layout should account for jet
blast effects caused by exiting aircraft on other aircraft that are
receiving or have completed deicing/anti-icing treatment and on
personnel and equipment performing duties. Jet blast velocities on
neighboring aircraft can cause a degradation of the protective film
coating of Type II fluids, leading to reduced holdover times. Reduced
holdover protection also results when taxiing aircraft recirculate snow
onto following aircraft when trailing separations are short. As AEA
states, *"Sufficient distance from the preceding aircraft must be
maintained as blowing snow or jet blasts can degrade the anti-icing
protection of the aircraft".* AC 20-117, *Hazards Following Ground
Deicing and Ground Operations Conducive to Aircraft Icing*, further
warns that in addition to the degradation effects of anti-icing
protection, *"Be aware that operations in close proximity to other
aircraft can induce snow, other ice particles, or moisture to be blown
onto critical aircraft components, or allow dry snow to melt and
refreeze".* Aircraft manufacturers are the primary source for jet blast
pressures and velocity curves.

**(2) Mitigation Measures.** Mitigation measures may be necessary at
deicing facilities to ensure jet blast does not damage parked ground
service equipment required at the facility, personnel shelter, and FAA
navigational facilities. AC 150/5300-13 describes means of minimizing
the effects of jet blast.

**3-6. ELECTRONIC MESSAGE BOARDS FOR OFF-GATE DEICING FACILITIES.** The
use of electronic message boards (EMBs) at off-gate deicing facilities
by the service provider (not ATCT) have increased the overall efficiency
of deicing/anti-icing aircraft and, additionally, improved the transfer
of information between flight crews and service providers. In general,
the primary purpose for installing EMBs is to (1) reduce verbal
communication between all involved parties; \[*caution -- radio
communication is still necessary to inform flight crews when to exit the
deicing pad*\]; (2) provide flight crews with clear, concise
information; (3) improve deicing pad operational safety and efficiency;
and (4) reduce ground congestion by removing personnel and equipment
from the deicing pad area after completing deicing/anti-icing
operations. If EMBs are installed, they should be installed in
accordance with SAE AS 5635*, Message Boards (Deicing Facilities)*. The
SAE aerospace standard defines the minimum content and appearance of the
electronic display, functional capabilities, design requirements, and
inspection and testing requirements for EMBs. One acceptable location
for EMBs is within the vehicle safety zones discussed in paragraph
3-4(d). Figures 3-5(a) through (c) illustrate the types of information
exhibited by EMBs at Toronto Pearson International Airport, Toronto,
Canada, and Montreal Pierre Elliot Trudeau International Airport,
Montreal, Canada.

**3-7. APRON DESIGNS FOR OFF-GATE DEICING FACILITIES.** Aprons for
deicing facilities must have a pavement design that supports the
anticipated aircraft loads and directs deicing fluid for collection.

**a. Pavement Designs.** The pavement must be either a rigid (concrete)
or flexible (asphalt) pavement and designed in accordance with AC
150/5320-6, *Airport Pavement Design and Evaluation,* and AC
150/5320-12, *Measurement, Construction, and Maintenance of Skid
Resistant Airport Pavement Surfaces*. Deicing pads should be grooved to
assist in channeling deicing fluids for collection and providing
aircraft and personnel better traction.

**b. Apron Grades and Surface Gradients.** Apron grades and adjacent
surface gradients must be in accordance with AC 150/5300-13. Apron areas
should direct flows away from deicing pad centerlines, fixed-fluid
applicators, vehicle safety zones, and crew shelter. If interior covered
drains are used, they must not create a hazard to aircraft and
personnel. AC 150/5320-5 provides guidance on high-strength covers.

**c. Limit of Apron Perimeter.** The perimeter of the facility's apron
must extend such that no aircraft surface being deiced/anti-iced extends
beyond it, and it will have a means for collecting or redirecting
deicing fluid runoff. One alternative is a trench drainage system.
Regardless of the collection alternative, it must not in itself become a
hazard to taxiing aircraft or personnel.

![](media/image12.jpeg){width="4.508333333333334in"
height="2.9097222222222223in"}

**Figure 3-5(a). Electronic message board instructing the pilot to
continue forward to the stop point of the deicing pad**

![](media/image13.jpeg){width="4.721527777777778in"
height="3.088888888888889in"}

**Figure 3-5(b). Electronic message board informing the pilot the
aircraft has reached the stop point of the deicing pad**

![](media/image14.png){width="2.9166666666666665in" height="2.75in"}

***Left-side -- Information Display (both images):*** Red 'Stop', Pad
Identification

***Right-side -- Information Display:*** Fluid Type, Time (Start of
Deicing) (top image);

repeat for Anti-icing, if required; ***alternating*** with Outside
Ambient Temperature (bottom image)

**Figure 3-5(c). An electronic message board *alternating information*
to the aircraft receiving deicing/anti-icing treatment**

This page intentionally blank.

##  {#section-1 .unnumbered}

## CHAPTER 4. AIRCRAFT ACCESS AND VEHICLE SERVICE ROADS

**4-1. AIRCRAFT ACCESS ROUTES.** Deicing facilities will have some form
of bypass taxiing capability to accept aircraft requiring treatment
without restricting other aircraft access to active runways. Besides
supporting departure demand for the anticipated weather conditions, this
feature may offer an aircraft a return route for re-deicing when it
exceeds its holdover time. The merging of taxiing routes serving the
facility with other taxiing routes should allow the ATCT easy
directional control to direct aircraft for deicing or clear the aircraft
for departure.

**a.** **Holding Bays**. Some airports do not have enough physical space
for facilities to have a separate taxiway for bypass taxiing capability.
One alternative to reducing potential bottlenecks is to expand or
construct a holding bay. The size of the holding bay should allow
aircraft the maneuverability to be deiced/anti-iced while permitting
subsequent aircraft bypass taxiing capability.

**b. Design of Taxiing Access Routes for Facilities.** Access taxiing
routes for facilities will be designed in accordance with AC
150/5300-13, AC 150/5320-6, and AC 150/5320-12. Additionally, taxiing
routes should---

**(1)** have a minimum of turns, taxiway intersections, and runway
crossings,

**(2)** avoid areas that require repeated ATCT clearances, and

**(3)** not create potential bottlenecks nor operational problems for
landing aircraft.

**4-2. VEHICLE SERVICE ROADS.** Deicing facilities may require vehicle
service roads or staging areas to operate more efficiently, to reduce
the likelihood of runway incursions by deicing vehicles and ground
service vehicles, or to operate the environmental alternative for
managing deicing fluid runoff. So as not to compromise the emergency
response times of aircraft rescue and fire fighting (ARFF) vehicles when
deicing vehicle traffic is heavy on a service road, pullover shoulders
should be constructed or similar provisions should be made.

**a. Operational Dependency.** Usually, centralized facilities depend
less on service roads than remote facilities because of their closer
proximity to the terminal apron areas. One possible means of lessening
the need for service roads at a centralized facility is to install
deicing fluid storage tanks and transfer systems or fixed-fluid
applicators. Remote deicing facilities are recommended to have a service
road when no other means, such as a nonactive taxiway, is available for
mobile deicing vehicles and service vehicles to reach the site. This
service road will provide authorized personnel the access necessary to
conduct outside-the-aircraft and pre-takeoff contamination checks and to
perform deicing/anti-icing treatment.

**b. Safety Dependency.** Reducing potential runway/taxiway incursions
by deicing vehicles and ground service equipment is a safety objective.
A service road is recommended when no other means is available to
separate deicing vehicles and aircraft traffic from sharing a common
taxiway route. For some airports, an extension to an existing service
road or perimeter road is sufficient. Depending on the airport's safety
programs, physical constraints, etc., service vehicles without the
benefit of a vehicle service road may still need to be escorted on
taxiway/runways.

**c. Environmental Dependency.** The environmental mitigation
alternative needed to manage deicing fluid runoff may require a service
road. For instance, a deicing facility with a detention basin may
require an extension of a perimeter road to allow airport vehicles to
reach the basin for monitoring and metering out permitted discharges. A
deicing facility with an underground storage tank or a concrete vault
that requires a hauling truck to siphon contaminants for proper disposal
may also need a service road.

**d. Service Road Design.** Service roads should accommodate deicing
vehicle widths and turning radii requirements. Vehicle dimensions and
other characteristics related to service road design are described in
SAE ARP 4806, *Aircraft Deicing/Anti-icing Self Propelled Vehicle,
Functional Requirements;* SAE ARP 1971, *Aircraft Deicing Vehicle --
Self-Propelled Large and Small Capacity;* and ISO 11077, *Aerospace --
Self-Propelled De-icing/Anti-icing Vehicles --Functional Requirements.*
If vehicles use remote staging areas, service roads should be located,
to the extent practicable, to minimize runway crossings, repeated ATCT
clearances, or airport escorting. Additionally, service roads should---

**(1)** have the handling capacity to permit the necessary number of
deicing vehicles to transport a quantity of fluid that equals the
facility's peak deicing fluid demand.

**(2)** have clearly defined circulation routes with the minimum of
taxiway and runway crossings to reduce potential incursions. Service
roads for airports operating under a SMGCS Plan may require vehicle stop
signs, stop bars, and other signs and marking to be installed where they
intersect an aircraft movement area operating under the plan.

**(3)** be located so as not to create an aircraft hazard or impede
emergency response times of ARFF vehicles.

**(4)** be bidirectional where vehicle traffic is heavy.

**(5)** avoid conflicts with future airport development.

**(6)** not create additional congestion and inconveniences to other
users.

## CHAPTER 5. DESIGN OF INFRA-RED AIRCRAFT DEICING FACILITIES

**5-1. OVERVIEW.** The predominant method for deicing airplanes relies
on the application of aqueous solutions of freezing point depressant
(FPD) fluids. For ***deicing*** operations, other methods have been
employed, such as the mechanical removal of certain types of
contamination from airplane surfaces or the placement of airplanes
within a heated hangar to melt or loosen contamination. For
***anti-icing*** airplanes, the only acceptable method continues to rely
solely on the application of an appropriate anti-icing FPD. Today, all
available FPDs are glycol-based products.

Recent developments in the ability of infra-red energy to deliver
sufficient, targeted energy to contaminated airplane surfaces, as
prescribed in paragraph 5-11, makes infra-red technology, ***in
conjunction with an FAA-approved airplane ground deicing/anti-icing
program,*** an alternative deicing method. This alternative method
offers airport authorities an environmental benefit because it is
supplemented with little or no FPD during the deicing process. However,
since infra-red energy can support only the deicing process, airplanes
requiring *anti-icing* protection must still require an application of
an appropriate anti-icing FPD.

This chapter provides design standards and recommendations for building
infra-red aircraft deicing facility (IDFs) using a new class of
infra-red devices intended for deicing operations; these differ from
devices used in the heating industry. Figure 5-1 illustrates an IDF with
an entrance taxiway and an infra-red deicing structure; an anti-icing
pad is just out of view.

**5-2. DESIGN AIRPLANE.** The design airplane used to design an IDF will
be, in many applications, a composite of several airplanes. A composite
allows the designer to take into account the most demanding airplanes'
physical characteristics in terms of size and shape. For example, the
composite takes into account maximum tail heights plus their shapes,
such as the T- shaped tail section of DeHavilland Dash-8s; vertical
heights of wings fitted with winglets, such as the Airbus 320; and
variations in fuselage lengths within an airplane family, such as the
Boeing 737 family.

**5-3. INFRA-RED DEICING FACILITIES (IDFs)**. IDFs have the following
basic components:

**a.** Entrance taxiway,

**b.** Infra-red deicing structure**,**

**c.** Nighttime lighting**,**

**d.** Computerized gas-powered infra-red energy unit (EU) system**,**

**e.** Facility operations shelter**,**

**f.** Anti-icing capability**,**

**g.** Exit taxiway**,**

**h.** Bypass taxing capability**,** and

**i.** Runoff mitigation measure.

As optional equipment, IDF may have ice detection cameras, as described
in paragraph 5-9.

**5-4. SITING OF INFRA-RED DEICING FACILITIES.** IDFs must be sited in
accordance with paragraph 2-2*, FAA Clearance and Separation Standards
Affecting Deicing Facilities.* For air traffic control towers to
initiate control and release of aircraft, the perimeter of the facility
must be marked in accordance with paragraph 3-4, *Pavement Surface
Markings for Off-gate Deicing Facilities*. With the improved holdover
times of current anti-icers, terminal or cargo ramp areas present
promising locations for siting IDFs. For some airports, however,
acceptable sites along a taxiway may better complement the type of
operation in use during the winter season. Regardless of the chosen
site, the ground surrounding an IDF needs to be properly graded and
prepared to support ARFF vehicles. The requirement for grading provides
responding ARFF crews with access to any section of the IDF.

![](media/image15.png){width="6.913194444444445in"
height="2.415277777777778in"}

**Figure 5-1. FAA Boeing 727-100 taxiing into an infra-red deicing
structure**

**5-5. ENTRANCE TAXIWAY.** IDFs will have an entrance taxiway designed,
marked, and lighted in accordance with AC 150/5300-13, *Airport Design;*
AC 150/5340-1, *Standards for Airport Markings;* and AC 150/5345-46,
*Specification for Runway and Taxiway Light Fixtures*. The section of
the entrance taxiway leading into the infra-red deicing structure must
be straight and long enough to permit the longest airplane to align its
entire fuselage with the taxiway centerline prior to entering the
structure.

**5-6. INFRA-RED DEICING STRUCTURE.** IDFs must have an infra-red
deicing structure where airplanes are deiced by an infra-red EU system.

**a. Modular Truss Design.** The structure must be designed in
accordance with the building code requirements for the jurisdiction
having authority. The structure must be of a modular truss design that
offers the owner the flexibility to (1) accommodate changes in airplane
physical characteristics and (2) relocate the above-ground portion of
the structure on a seasonal basis. The structural components must be of
an interchangeable type that offers a range of sizes from the same basic
structural components in terms of expandable widths, lengths, and
heights, each being independent of the other.

**b. Modular Truss Construction and Framing Materials.** Modular truss
components used for framing must be made of an aluminum alloy or steel.
Steel structures must be galvanized in accordance with ASTM A 123,
*Standard Specification for Zinc (Hot-Dip Galvanized) Coatings on Iron
and Steel Products,* to resist corrosion. Each supporting column must be
designed and anchored---in accordance with the building code
requirements for the jurisdiction having authority---to resist imposed
static and dynamic forces, such as wind loads and snow loads. All
components, including cross members, fasteners, and bolts, must be
positively secured to protect against loosening and the possibility of
foreign object damage to airplane turbine engines and propellers.

**c. Fabric Cover.** IDFs must be covered by a fabric material (walls
and roof) that is flame-resistant in accordance with the large-scale
test in National Fire Protection Association (NFPA) 701, *Standard
Method of Fire Tests for Flame Propagation of Textiles and Films.*
Furthermore, the fabric cover must be easy to repair when damaged and of
a PVC-coated fabric, as opposed to laminated, to improve durability and
to protect the base fabric from ultraviolet light degradation.

**d. Lightning Protection.** The structure must be fitted with lightning
protection in accordance with NFPA 780, *Standards for the Installation
of Lightning Protection Systems.*

**e.** **Structure and Installation Design Codes.** The structure must
be designed in accordance with the building code requirements for the
jurisdiction having authority.

**f.** **Fire Safety Codes.** The structure must be designed in
accordance with fire code requirements for the jurisdiction having
authority.

**g. Electrical Code.** Electric service for the structure must be
designed in accordance with the electric code requirements for the
jurisdiction having authority. At a minimum, electrical service must be
installed in accordance with the provisions for aircraft hangars
contained in *Article 513, Aircraft Hangars,* of NFPA 70, *National
Electrical Code^®^*. Furthermore, all wiring not enclosed in
conduits/raceways must be adequately supported, laced, or banded to
reduce wear and damage as the result of jet blast or prop wash.

**5-7. NIGHTTIME LIGHTING.** The IDF must provide nighttime lighting
within the infra-red deicing structure and, if constructed, for the
exterior anti-icing pad. Nighttime lighting helps ground personnel
perform deicing/anti-icing processes and airplane inspections more
effectively. Interior lighting must be restricted to electric. Lighting
for the exterior anti-icing pad must be in accordance with paragraph
2-7*, Nighttime Lighting*.

**5-8. SIZING INFRA-RED DEICING STRUCTURES.** The size of infra-red
deicing structures must be determined by clearance requirements that
separate the structure framing/infra-red EUs from the design airplane.

**a. Length of Structure.** The length of the structure must equal the
length of the design airplane fuselage plus a length for an overhead
protective cover (PC). The PC, which is equally divided front and back
of the fuselage, serves to reduce or eliminate the amount of falling
precipitation onto airplane surfaces. The PC length will be in
accordance with table 5-1. Sites customarily experiencing large
horizontal dispersion of falling snow and/or frozen precipitation, as
can result from strong winds, can minimize such dispersions by orienting
the facility centerline perpendicular to such winds.

**b. Height of Structure.** The height of the structure must be such
that the closest point of the infra-red EUs and structural framing
clears the most demanding airplane tail section by 10 feet (3.0 m). Care
in selecting this dimension is necessary since the vertical heights of
airplanes vary according to tire pressures and taxiing weights, e.g.
operating design empty weight versus maximum design taxiing weight.
Therefore, the designer must take into account the maximum height of all
tail sections and their shape as provided by the airplane
manufacturer(s).

**c. Roof Size.** The roof of the structure must be arched to maximize
the delivered radiant energy by the infra-red EU system and thereby
reduce deicing times. Furthermore, the arched-roof must be designed with
open ends and be free of ceiling pockets to eliminate the accumulation
of engine exhaust and other vapors. In accordance with NFPA 409,
*Standard on Aircraft Hangars,* a 10-foot (3.0 m) clearance must be
provided between the arched framing/infra-red EUs and the most demanding
airplane wing configuration, i.e., height of wingtips and winglets. The
designer needs to take into account height variations of wingtips,
especially for airplanes with winglets, when airplanes are not fully
loaded with fuel. For example, Boeing publication *D6-58326-1, 747-400
Airplane Characteristics for Airport Planning,* shows that winglets on
the Boeing 747-400 range from approximately 22 feet (6.7 m) to almost 31
feet (9.3 m) above the ground. The designer must use the highest ground
clearances provided by airplane manufacturers.

**d. Width of Structure.** The width of the structure must provide the
clearance measured horizontally between wingtips/winglets and the
structural framing/infra-red EUs in accordance with table 5-2.

**e. Wall Egress**. Each wall must have one egress between two adjacent
columns to provide an additional evacuation route for passengers during
an emergency. The number of openings must be in accordance with the
jurisdiction having authority, but each opening must not be less than 4
feet (1.2 m) by 8 feet (2.5m). The egress must be located behind the
wing section and prominently labeled and lighted. If the jurisdiction
having authority requires the use of doors, then the doors must be of a
non-locking type that open outwards.

**f. Floor Design.** The floor must be designed to carry the maximum
anticipated taxiing weight of the design airplane in accordance with
paragraph 3-7(a), *Pavement Designs*. The floor must be sloped to allow
for drainage. If an infra-red deicing structure is placed over an
existing taxiway, the taxiway width must be expanded up to the
supporting structural columns of the structure. In this case, the
transverse grade of the taxiway will be continued for the full-expanded
width. The portions of floor that are wider than the existing taxiway
must have a load-bearing capacity for the expected vehicle traffic
within the structure. The edges of the floor in all cases must be free
of any type of continuous curbing.

**g. Drainage Design.** The floor must be designed to prohibit meltoff
and other runoff from ponding within the structure and direct runoff for
proper treatment. Any interior drains should be located near the
perimeter of the floor to minimize their exposure to aircraft and
vehicular traffic. When used, high-strength drainage boxes and covers
must be designed in accordance with AC 150/5320-5. Additionally, the
design of the drainage system must take into account the ability of the
ARFF service to respond unimpeded to emergencies and passengers to
evacuate the structure safely. For example, the drainage system leading
away from the structure must not be of an open ditch design.

**h. Floor Markings.** The floor must have two types of markings. First,
the floor must be marked with a taxiway centerline in accordance with AC
150/5340-1. Second, the floor must be marked with a nose wheel stop mark
to indicate the proper placement of airplanes under the infra-red EU
system. The facility operator should determine the shape and color of
the stop mark. Since the infra-red EU system offers the operator the
flexibility for zonal application of energies---that is, energizing only
portions of the system---more than one stop mark may be needed to
process smaller airplanes.

**5-9. OPTIONAL EQUIPMENT -- ICE DETECTION CAMERAS.** Infra-red deicing
structures may have as optional equipment ice detection cameras that
allow facility operators to scan airplane surfaces for the presence of
frozen contamination before and after airplanes are exposed to infra-red
energy. The cameras must meet the requirements of SAE AS 5116, *Minimum
Operational Performance Specification for Ground Ice Detection Systems*.
Cameras may be either a hand-held system or fixed system with color
monitors that show degrees of frozen contamination. The color monitor
for hand-held cameras are built into the camera itself, while for a
fixed system, the color monitor is a separate piece of equipment. If a
fixed system is used, the cameras should be placed in a manner that
maximizes the surface viewing areas of airplanes.

  ------------------------------------- ---------------------------------
  Airplane Design Group (ADG)           Protective Cover Length***^1^***

  ADG II and Smaller                    20 feet (6.1 m)

  ADG III and Larger                    30 feet (9.1 m)
  ------------------------------------- ---------------------------------

Note: 1. PC is equally divided front and back of the fuselage.

#### Table 5-1. Protective cover lengths

  ------------------------------------- ---------------------------------
  Airplane Design Group (ADG)           Clearance Distance

  ADG II and Smaller                    10 feet (3.0 m)

  ADG III                               15 feet (4.6 m)

  ADG IV and Larger                     20 feet (6.1 m)
  ------------------------------------- ---------------------------------

#### Table 5-2. Horizontal clearances

**5-10. FACILITY OPERATIONS SHELTER.** The infra-red deicing structure
must have an enclosed, temperature-controlled shelter for facility
personnel, with a separate operations room to house the computer system
that controls the infra-red EU system, a printer, color monitor(s) for
the fixed infra-red ice detection camera(s), telephones, and other
equipment necessary to the operation. The separate operations room is
intended to eliminate inadvertent distraction to system operator(s). The
operations room must have a window(s) that allows personnel running the
infra-red EU system a full view of the operation. The shelter must be
located in accordance with the clearances specified in table 5-2. A
suitable portable fire extinguisher(s) must be provided in accordance
with NFPA 10, *Standard for Portable Fire Extinguishers.*

**5-11. COMPUTER-CONTROLLED GAS-POWERED INFRA-RED EU SYSTEMS.**
Gas-powered infra-red EU systems must deliver sufficient radiant energy
at appropriate wavelengths that target specific types of contamination
without damaging airplanes. Furthermore, systems must be
computer-controlled to ensure greater operational control and improved
efficiency to remove contaminates. Computer control allows specific
infra-red EU systems to vary their energy levels and exposure times
independently for zonal applications. Thus, operators can tailor the
deicing process to tackle differences in airplane types and sizes and
variations in the types and thickness of contamination adhering to the
airplane. Therefore, systems must deliver infra-red energy in accordance
with the two-part test criteria from the following paragraphs.

An independent lab must evaluate the manufacturer's system to be
installed at the airport and analyze the actual energy levels that
airplanes will be subjected to. The testing parameters will allow the
flexibility for conducting system evaluations either outdoors
(preferable due to the separation requirements of the test and limit the
size of infra-red EU systems) or in a very large cold chamber. The FAA
reserves the right to retest all manufacturer's infra-red EU systems at
its discretion.

**a. Purpose of Contamination Removal and Heated Panel Tests.**
Acceptable infra-red EU systems pass two interrelated tests. Test
procedure (TP) #1, Contamination Removal, evaluates the system's
capacity to deliver sufficient focused infra-red energy to remove
artificially produced ice layers of specified thicknesses from test
panels within specified time frames. Test procedure (TP) #2, Heated
Panel, evaluates the system's performance settings used in TP #1 to
evaluate the potential for the system to overheat uncontaminated
(cleaned) test panels beyond a prescribed maximum surface temperature.
System evaluations must be conducted in accordance with the test methods
outlined in paragraph 5-11(d). Although the evaluation tests are based
on a 10-foot (3.05 m) separation between the panels and infra-red EU
system, the majority of the infra-red EUs within a system in field
applications will operate at much greater distances. Infra-red EU
systems are intended to work effectively at greater distances, such as
20 to 30 feet (6 to 9 m) or more from some aircraft sections. For
example, some infra-red EUs aimed at the midwing sections and the upper
fuselage will be placed much more than 10 feet away (3 m).

**b.** **Test Locations and Conditions.** Independent labs must conduct
evaluations either in a large cold chamber or, preferably, outdoors
under the following conditions: cold chamber or ambient outdoor
temperature at or below 28 °F ± 2 °F (--2.5 °C ± 1.0 °C) with winds not
exceeding 10 mph (16 km/hr.)

**c. Independent Testing Lab Report.** The independent testing lab
report must contain---

**(1)** for TP #1, the actual observed times necessary to remove
completely the contamination thicknesses for each tested panel,

**(2)** for TP #2, a temperature rise over time profile graph that notes
the highest recorded temperature for each tested panel,

**(3)** photographs showing the system's setup over the inclined
supporting structure that holds the test panels,

**(4)** separation distances from the infra-red EUs to the test panels,

**(5)** ambient outdoor or cold chamber temperature and wind conditions
at the start and conclusion of the evaluations, and

**(6)** statement of success or failure for the candidate system.
Specific failure(s) of a testing requirement(s) will be noted.

For pass/fail determinations, complete ice removal is defined as the
absence of ice, which has undergone a physical change to water or vapor,
from the entire upper surface of a test panel, excluding water droplets
from the drip edge. Also, since the testing panels are inclined,
portions of ice sheets that disbond and slide off the testing panels due
to the effect of gravity are considered to be "completely removed",
i.e., meeting the intent of TP #1.

**d. Testing Methods and Materials for Contamination Removal and Heated
Panel Tests.**

**Testing Materials:**

**(1) Test panels,** six in all, will be 3-foot square by ⅛^-^inch thick
flat sheets of aluminum alloy SAE Aerospace Material Specification (AMS)
4037 in accordance with AMS 1428, *Fluid, Aircraft Deicing/Anti-icing,
Non-Newtonian (Pseudo plastic), SAE Types II, II and IV*, latest
edition.

**(2) Artificial ice** will be produced by freezing ASTM D 1193,
*Standard Specification for Reagent Water*, Type IV water.

**(3) Set up an inclined supporting stand** (ISS) to secure and support
three separated test panels simultaneously in an inclined position. The
ISS must be able to secure test panels so the lower drip edge of the
test panels are 3 feet ± 1 inch (91.5 cm ± 2.5 cm) above the floor and
provide a +10 degree ± 1.0 degree incline from the horizontal. The ISS
must have a means to eliminate sagging of the test panel, which in turn
may cause breakage of the artificial ice layer (for example, ISSs should
have a center structural member to eliminate sagging). Furthermore, ISSs
should be on wheels/casters to allow them, once test panels are secured,
to be rolled into position beneath the candidate infra-red EU system.

### Test Procedure: TP #1

**Contamination Removal**

**Step 1: Setup of Overhead Infra-red EU System.** Position the
candidate infra-red EU system directly above the ISS with three clean
test panels (see 5-11(d)(3) for height requirements) such that the
lowest part of the system (EU housing) is at a distance of 10 feet ± 1
inch (3.05 m ± 2.5 cm) above the top of the three test panels.
Regardless of the system's arrangement, all EUs must be at least 10 feet
(3.05 m) away from the test panels. Mark the location of the ISS on the
floor. Floor markings will later be used to reposition the ISS with
secured test panels for actual test runs.

**Step 2:** **Artificial Ice.** Prepare six test panels, individually
numbered with an artificially produced ice layer. Test panels will have
temporary walls attached to their edges to create a ½-inch (1.27 cm)
high dam effect. (The dam effect can be obtained by using paraffin wax,
silicon, or caulking compound to hold water.) Pour Type IV water into
the six test panels to obtain three test panels with a depth of ⅛ inch ±
^1^/~16~ inch (0.32 cm ± 0.16 cm) and three test panels with a depth of
¼ inch ± ^1^/~16~ inch (0.64 cm ± 0.16 cm). To help measure the water
depth, five small rubber washers having the prescribed depths can be
used. The five rubber washers will be placed in a "T pattern" (not an "X
pattern") one centered and four placed approximately 6 inches (15.25 cm)
from the edges. Cold store test panels with washers at 25 to 28 °F (-4.0
to -2.5 °C) for at least 8 hours to allow the Type IV water to freeze
completely. All temporary walls are to be removed carefully prior to
exposing test panels with infra-red energy.

**Step 3: Inclined Test Panels.** Carefully place three test panels with
¼-inch ice thickness, separated horizontally by 1 foot (30.5 cm), onto
the ISS. Make sure the lower edge of the test panels are slightly below
the ISS, approximately ½ inch (1.25 cm), to allow ice melt to flow
freely off the inclined test panels. *Precaution:* Panels need to be
secured in a "flat as possible" manner to eliminate ice breakage due to
sagging or bending of the test panels.

**Step 4: Time Recording.** After the infra-red EU system achieves
equilibrium (expected settings in actual field operations), roll the ISS
with secured test panels underneath the system and reposition the ISS
using the step #1 floor markings. Commence time recording immediately.
The clock is stopped for each test panel once all observable ice
contamination is removed from the entire upper surface. Record the time
required for all three test panels. Test panels can have water droplets
on the drip edges, and panels need not be completely dried. The longest
time duration recorded for this ice thickness will be used to determine
acceptance in accordance with table 5-3. Repeat steps #3 and #4 with the
⅛-inch contaminated test panels.

### Test Procedure: TP #2

**Heated Panel**

**Step 1: Setup of Overhead Infra-red EU System.** Evaluate the
identical infra-red EU system and ISS setup used for TP #1, step 1.

**Step 2: Acclimated Test Panels.** Cold store six clean, uncontaminated
test panels at 25 to 28 °F (-4.0 to --2.5 °C) for 3 hours.

**Step 3:** **Inclined Test Panels.** Secure three clean, uncontaminated
test panels in the same position as described in TP #1, step 3.

**Step 4:** **Thermocouple Placement.** Attach two thermocouples down
the middle of each test panel so they record the surface temperature of
the test panel. Place the first thermocouple 1 foot (30.5 cm) from the
top of the test panel. Place the second thermocouple 1 foot (30.5 cm)
below the first thermocouple. Cover the housing of the thermocouple in
such a manner as to minimize a temperature rise in the thermocouple
itself as a result of infra-red energy exposure. Thermocouples used must
have an operating temperature reading range from at least +10 to +250 °F
(-12 to +121 °C) with a tolerance of 1 ° F (0.5 °C).

**Step 5: Time Recording.** Energize the infra-red EU system to the same
power settings used to remove the ¼-inch ice contamination in TP #1,
step 4. Once the system is in equilibrium, reposition the ISS and
commence time and temperature recording. Record the continuous surface
temperature rise of each test panel for a total exposure time of 10
minutes. Repeat TP #2, steps 3, 4, and 5, for the ⅛-inch power settings.
Acceptable systems are those where the maximum temperature rise as
measured in step 5 of TP #2 for all six test panels remains below 150 °F
(65.5 °C).

+---------------------------------+------------------------------------+
| Contamination Type and          | Maximum Removal                    |
| Thickness                       |                                    |
|                                 | Time Permitted                     |
|                                 |                                    |
|                                 | (minutes)                          |
+---------------------------------+------------------------------------+
| ⅛-inch Ice                      | 8                                  |
+---------------------------------+------------------------------------+
| ¼-inch Ice                      | 15                                 |
+---------------------------------+------------------------------------+

**Table 5-3. Acceptance criteria for contamination removal by infra-red
EU systems**

**5-12. INSTALLATION OF INFRA-RED EU SYSTEMS.** Installed infra-red EU
systems must be gas-fueled. Individual infra-red EUs that comprise the
system will be at least 10 feet (3.0 m) away from airplane surfaces for
the airplanes expected to use the facility. Gas-fueled infra-red EU
systems, which include the gas supply and, if present, storage vessels,
must be installed in accordance with NFPA 54, *National Fuel Gas Code*.
The main gas supply system(s) will be equipped with manually operated
control valves and emergency safety shutoff valve(s). The manually
operated valves must be located at strategic points inside and
immediately outside the structure so the main gas supply can be shut
down quickly in the event of an emergency. A placard must indicate the
location of all red-coded control and emergency safety shutoff valve(s).

**5-13. INFRA-RED EU SYSTEM CONFIGURATION.**

**a. Infra-red Energy Zones.** The entire infra-red EU system must be
placed in an overhead configuration that provides effective infra-red
energy to the design airplane. Additionally, the configuration must
consist of independently operated energy zones that allow the operator
to use all energy zones in the system or pre-selected energy zones. For
example, the operator could use only those energy zones that are better
suited for small airplane applications.

**b. Maintenance.** Infra-red EU systems must be located in areas that
do not subject them to damage by aircraft or ground equipment.
Provisions must be made to ensure accessibility to individual infra-red
EUs for scheduled maintenance purposes.

**5-14. COMPUTER HARDWARE/PERFORMANCE.**

**a. Hardware.** Infra-red EU systems must employ computer hardware
consisting of a processing unit, color monitor, and printer. The
computer must have the operating capability to perform software routines
with sufficient speed and memory for data evaluation/records.

**b. Software Routines.** Software routines may be initiated by keyboard
and/or by a touch screen monitor. The software must have a routine that
automatically self-imposes a system shutdown when the system itself
acknowledges a problem. Furthermore, the software must have routines
that allow the operator to---

**(1)** pre-warm the structure,

**(2)** regulate the amount of focused infra-red energy through variable
power settings to remove the various types of contamination and various
airplane configurations,

**(3)** regulate the duration of infra-red energy application for each
power setting,

**(4)** energize specific infra-red EUs and at different infra-red
energies for zonal applications,

**(5)** shutdown the entire system with a single command button,

**(6)** print records detailing airplane designation, time of entry to
structure, energy settings used and their duration, and time of
completion, and

**(7)** receive warning(s) as required by the authority having
jurisdiction to indicate a problem has occurred with the infra-red EU
system.

**5-15. ANTI-ICING CAPABILITY.** IDFs will provide the facility operator
with the capability to anti-ice airplanes in one of two ways.

**a. Interior Anti-icing Operations.** The clearance criteria for sizing
infra-red deicing structures is such that sufficient clearance is
afforded for deicing trucks to perform anti-icing operations within the
structure. Depending on where the infra-red deicing structure is placed,
a paved vehicle staging area may be necessary. That is, deicing trucks
will have a staging area(s) that allows untreated and treated airplanes
to enter and exit the structure safely.

**b. Exterior Anti-icing Pad.** If a determination is made to perform
exterior anti-icing operations, then a dedicated uncovered anti-icing
pad will be required. Generally, the anti-icing pad will be located
directly in line with the infra-red deicing structure. It is recommended
that the anti-icing pad, which consists of the aircraft parking area and
the vehicle maneuvering area, be at least 20 feet (6 m) from the opening
of the infra-red structure. The anti-icing pad must be marked with a
taxiway centerline and lighted in accordance with AC 150/5340-1 and AC
150/5345-46. The length of the anti-icing pad must be in accordance with
paragraph 3-1, *Aircraft Deicing Pads*. The anti-icing pad must be 10
feet (3 m) wider than specified in paragraph 3-1. The 10-foot (3 m)
increase is used to provide a 10-foot (3 m) vehicle safety zone for
parking and staging mobile deicing trucks.

**5-16. EXIT TAXIWAY.** IDFs must have an exit taxiway designed, marked,
and lighted in accordance with AC 150/5300-13, AC 150/5340-1, and AC
150/5345-46. The section of the exit taxiway leading out of the
infra-red deicing structure must be straight and long enough to permit
the longest exiting airplane to completely clear the structure before
initiating a turn.

**5-17. BYPASS TAXIING CAPABILITY.** IDFs will provide a taxiway route
to by-pass the IDF in accordance with paragraph 2-8, *Bypass Taxiing
Capability.*

**5-18. RUNOFF MITIGATION.** IDFs must have a runoff mitigation
structure(s) that permits proper disposal of glycol-based products in
accordance with Chapter 6*, Water Quality Mitigation*.

## CHAPTER 6. WATER QUALITY MITIGATION

**6-1. RUNOFF MITIGATION STRUCTURES.** Since deicing/anti-icing fluids
are chemical products that have environmental consequences that affect
the water quality of receiving waters and the aquatic communities that
use those waters, deicing facilities must have runoff mitigation
structures. The recommended structures are those that compose a
mitigating alternative that collects and retains runoff for proper
disposal or recycling. In terms of structural best management practices,
this approach to "control the source" offers airport managers an
effective and economical means of complying with storm water permitting
requirements. AC 150/5320-15, *Management of Airport Industrial Waste*,
provides additional best management practices for mitigating various
types of pollutants from entering storm water runoff conveyances.

**a. Treatment Advantages.** The approach to "control the source" offers
two treatment advantages. First, it lessens the difficulty of dealing
with the facility's deicer runoff by isolating it from airfield storm
sewers or from terminal areas that do not divert seasonal flows of
glycols. Second, deicing facilities enhance the feasibility and economic
benefits of recycling glycols by collecting higher glycol
concentrations, as compared to drainage systems where glycols are
further diluted with other runoff and precipitation.

**b. Treatment Parameters.** Biochemical oxygen demand (BOD) and
toxicity are the primary runoff effects the alternative needs to
mitigate. The additives in fluids may have an effect on the overall
biodegradability. Depending on the type of discharge permit, the
alternative would need to monitor specific items, generally based on
BOD~5~, chemical oxygen demand (COD), total organic carbon (TOC), total
suspended solids (TSS), oil/grease, pH, and flow rate limits.

**6-2. MITIGATION ALTERNATIVES.** The mitigation alternative should
allow users of the deicing facility continued use of deicing fluids
within the framework of Federal, state, and local storm water runoff
regulations (discharge permits). The FAA strongly recommends the
Federal, state, or local environmental authority having jurisdiction
review the proposed alternative to verify its effectiveness in meeting
water quality permit requirements (see paragraph 1-3, *Project Input*).
Prior to final selection, all alternatives should be evaluated on a
lifecycle cost basis to avoid an accepted long-term alternative with a
short useful life; for an example, see paragraph 6-3, *Publicly Owned
Treatment Works (POTWs).* Additionally, it should reflect the best
alternative afforded by the facility's site and integration with the
airport master drainage plan. A few alternatives are an---

**a.** off-airport biochemical treatment of facility runoff at POTWs by
way of a sanitary sewer. See paragraph 6-3, *Publicly Owned Treatment
Works,* for additional guidance.

**b.** on-airport detention basin with a pump station for discharging
metered runoff to receiving waters by an airport storm sewer. See
paragraph 6-4, *Detention Basins,* for additional guidance.

**c.** on-airport anaerobic biochemical reactor for pre-treatment of
runoff prior to discharge to POTWs or a detention basin. See paragraph
6-7, *Anaerobic Bioremediation Systems.*

**d.** on-airport underground storage tanks (USTs) or concrete vaults
for detention of runoff that hauling tankers can pump out for proper
disposal. Airports lacking the physical space for detention ponds can
consider placing USTs near the deicing facility. See paragraph 6-5,
*Underground Storage Tanks (USTs),* for additional guidance.

**e.** on-airport recycling system. See paragraph 6-6, *Recycling Glycol
Fluids,* for additional guidance.

**f.** diversion boxes for diverting seasonal glycol runoff to a
specific location, such as a detention basin. Depending on the site and
storm water permitting requirements, one of the above alternatives
and/or other technologies working in tandem should provide the airport
manager with an effective alternative acceptable to Federal, state, and
local environmental authorities.

**6-3. PUBLICLY OWNED TREATMENT WORKS (POTWs).** Off-airport biochemical
treatment of facility runoff at POTWs is a proven mitigation
alternative. This alternative normally requires the airport manager to
monitor flow volumes and pretreat glycol-contaminated storm water to
protect the receiving POTW facility; for an example, see paragraph 6-7,
*Anaerobic Bioremediation Systems.* Areas of probable pretreatment are
high BOD~5,~ COD, TOC, TSS, pH, and oil/grease. Of these, treatment of
glycol BOD loads is of primary concern since some data show an impact
load of approximately 3,000 times that of raw human sewage. To protect
POTWs, the U.S. Environmental Protection Agency (USEPA) developed a
national pretreatment strategy (1977) under the Clean Water Act. The
regulations were published as Title 40 Code of Federal Regulations
(CFR), Part 403, *General Pretreatment Regulations for Existing and New
Sources of Pollution.* Regardless of the size of the surrounding
community, airport authorities considering this alternative should not
only evaluate the POTW's current capacity, but whether it can accept
both future load demands from the airport and a growing community.

**6-4. DETENTION BASINS.** For airports with available physical space,
an economical alternative to treating "first flush" runoff from deicing
facilities is with a single or series of detention basins. The state or
local authority having jurisdiction generally sets construction and
design standards. Impermeable liners to protect the groundwater and/or
monitoring wells to detect breached liners will likely be required.

**a. Sizing.** The biodegradability rate, which varies by glycol types,
is a primary factor for determining basin capacity. Basin capacity can
be reduced by taking into account the slower microbial activity during
the winter season and the greater concentration of available oxygen in
colder water. Dissolved oxygen is normally expressed in parts per
million or other concentrations. Detention of ethylene glycol, which
degrades quicker than propylene glycol, permits earlier metered
discharges and, thus, reduced basin capacity.

**b. Mechanical Aeration.** The quick consumption of available oxygen
levels within basins by glycol can lead to anaerobic conditions (lack of
oxygen). This condition leads to undesirable odors due to the adverse
impacts to bacterial generation necessary for glycol degradation. A
recommended corrective action is to install a mechanical aeration system
to replenish oxygen levels. This supplemental acceleration of
biodegradation, and earlier discharging of glycols, further reduces a
basin's capacity. The installed system should maintain dissolved oxygen
levels at the level that places the alternative in environmental
compliance. For some basins, pump stations and force mains may be
required if the discharge cannot reach the desired outfall locations.

**c. Wildlife Management.** AC 150/5320-15 and AC 150/5200-33,
*Hazardous Wildlife Attractants On or Near Airports,* provide
recommended configurations and site location for detention basins to
minimize potential wildlife issues. Non-enclosed detention basins must
not be situated under or adjacent to runway approaches.

**d. Other Features.** Additional design features may be necessary if
runway deicers containing urea or other effluents are collected within a
basin that contains nutrients for plant growth. For instance, the growth
of algae blooms under the right conditions may be considered suspended
solids by some environmental authorities. Their inclusion in the TSS
discharge limit may cause this alternative to exceed permitted levels.

**6-5. UNDERGROUND STORAGE TANKS (USTs).** UST systems that collect
ethylene glycol deicing fluids are regulated under the USEPA UST
regulations, i.e., 40 CFR, Part 280, *Technical Standards and Corrective
Action Requirements for Owners and Operators of Underground Storage
Tanks (UST),* and Part 281, *Approval of State Underground Storage Tank
Programs.* Though other types of glycols are available that may not be
regulated and thus not require USTs, UST systems have the potential to
collect a regulated substance such as aviation fuel. Because of this
potential and future use of ethylene glycol-based fluids by tenants, the
FAA recommends this alternative be designed in accordance with
applicable USEPA and state UST regulations. For facilities used on a
yearly basis, this alternative may collect regulated substances when the
deicing pads are used for washing the exterior of aircraft. If a UST is
the final collection point, a rigid pad with catch basin may be required
for hauling tankers.

**6-6. RECYCLING GLYCOL FLUIDS.** Depending on the nature of the runoff
and economics, it may be possible to use improved technologies that
recycle spent glycol fluids collected at concentrations of 5 percent
and, under certain conditions, even lower percentages. The recycling of
fluid types that offer longer holdover times compared to Type I fluids
is normally more demanding because of special polymers. This problem,
however, is resolved by adding an extra processing step, thus making
recycling an economical alternative. Recycling provides airport
management with two valued resources: recycled glycol and water. In
addition to recouping some of the chemical cost for glycol and the
utility cost for water, other recycling benefits may be reduced sludge
disposal costs incurred by other mitigation alternatives and less
physical space needed for equipment.

**a. Recycled Glycol Fluids.** Recycling glycol may lower disposal cost
of effluent through the resale of recovered product to fluid
manufacturers or to other secondary markets. Prior to using recycled
glycols as the primary aircraft deicer/anti-icer fluid, recertification
in accordance with established industry standards is necessary, e.g.,
SAE, ISO. Also, recycled glycol fluids may be reused on the airfield
pavements if they meet the appropriate glycol-based runway fluid
specifications in AC 150/5200-30, *Airport Winter Safety and
Operations.*

**b. Recycled Water.** The limited availability and high cost of water
for some airports may make recycling a cost-effective runoff mitigation
alternative. Airport management can commit recovered water, if
permitted, to irrigate airport landscapes, wash airport/aircraft
equipment, or use for other non-potable water purposes.

**6-7. ANAEROBIC BIOREMEDIATION SYSTEMS.** Anaerobic bioremediation
systems in conjunction with POTWs or detention basins can be an
effective means of disposing of glycol-contaminated storm water. The
bioremediation system generally consists of a glycol contaminated storm
water collection and storage system, a bioreactor treatment system, and
a gas/heat recovery system. Today, many POTWs will only accept limited
quantities of glycol-contaminated storm water. Anaerobic systems,
depending on the airport's discharge permit, can reduce BOD~5~
concentration levels sufficiently to permit unrestricted disposal to a
POTW. For example, one airport-tested system reduced the

oxygen demand of incoming glycol-contaminated runoff by over 98 percent.
For those cases where POTWs continue to impose discharge restrictions,
the lowered BOD~5~ concentration level may allow an increase to the
permitted discharge rate. Regarding detention basins, the presence of
high glycol concentrations usually makes complete treatment more
difficult. Treatment under such conditions normally requires
considerably more energy for aeration systems and produce large amounts
of excess biomass, which, in turn, needs proper disposal. Anaerobic
systems not only reduce high BOD~5~ concentration levels but produce
significantly less biomass. When biomass is a problem, anaerobic systems
can use activated carbon as the media for attaching the biomass.
Furthermore, these systems have demonstrated an additional ability to
remove or lower to non-detectable levels "additive packages" that are
necessary in deicer products from collected runoff. An economic benefit
of the anaerobic process is that it converts glycol in runoff to methane
gas that can be used for heating.