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3.5 Drafting Guidelines

It is important to know the difference in elevation between the pump and the water source when drafting water from a pond or stream. When drafting water, the air at atmospheric pressure is removed from the hose line, creating a vacuum (negative pressure) within the pump chamber. The atmospheric pressure (weight of air) on the water's surface forces the water up through the suction hose to the pump.

The maximum height to which an engine or pump can lift water is determined by the atmospheric pressure. At sea level, the atmosphere exerts an average pressure of 14.7 pounds per square inch (psi). Atmospheric pressure will vary due to changes in the weather. However, these changes tend to moderate themselves so that the average pressure will tend to go back toward 14.7 pounds per square inch. That is why it is safe to use this value of 14.7 pounds per square inch as a constant for calculations.

Example 1 - What would be the maximum height of water that a pressure of 14.7 pounds per square inch would be capable of sustaining?

Step 1. Find the appropriate conversion in Table 3.1.
1 psi = 2.304 ft

Step 2. Set up the cancellation table so all units will cancel, except the desired unit, feet, to calculate the lift created by 14.7 pounds per square inch. 
cancellation table

The atmospheric pressure would be capable of sustaining a column of water 33.9 feet in height.
 

If a pump could produce a perfect vacuum, the maximum height to which it could lift water at sea level would be 33.9 feet, as shown in Example 1. This number is the maximum theoretical lift, but in practice no pump built can produce a perfect vacuum. A fire engine in fairly good condition can lift water two-thirds of the theoretical lift, 2/3 × 33.9 = 22.5 feet. This height is called the maximum attainable lift. With an increase in elevation above sea level, atmospheric pressure decreases, thus reducing the vertical distance from the water source where drafting can be done effectively.
 

ELEVATION EFFECTS

For every 1,000 feet of change in elevation, there is a loss of 1 foot in suction or lift and a 0.5 pounds per square inch decrease in atmospheric pressure. 

Example 2 - An engine can lift water 22.5 feet at sea level. The same engine is driven to a fire at an elevation of 2,000 feet above sea level. What lift can the engine produce at this elevation?

Step 1. Use the conversion given for elevation change. A 1-foot loss = 1,000-foot elevation change

Step 2. Set up the cancellation table so all units will cancel, except the desired unit, feet, to calculate the loss in lift for a 2,000-foot elevation. (See Section 2.1 to review unit cancellations if desired.)

cancellation table

Step 3. Subtract the resulting value from the number of feet that can be lifted at sea level. 22.5 ft - 2 ft = 20.5 ft

This pump can lift 20.5 feet of water at a 2,000-foot elevation.
 

Example 3 - Larry is 16 feet above his water source, at an elevation of 4,000 feet. Will Larry still be able to draft water?

Step 1. Find the appropriate conversion/estimation in Table 3.1 to calculate the decrease in possible lift. At sea level, attainable lift is 22.5 feet.

Step 2. Set up the cancellation table so all units will cancel, except the desired unit, feet (loss), to calculate the loss in lift. Due to the elevation, the sustainable lift decreases by:

A 1,000-foot increase in elevation = 1-foot loss

cancellation table

Step 3. Calculate the adjusted attainable lift. The maximum attainable lift would now be: attainable lift - decrease due to elevation = adjusted attainable lift 22.5 ft - 4 ft = 18.5 ft

Step 4. Determine whether drafting is still possible. attainable lift = 18.5 ft so Larry would still be able to draft water up to a vertical distance of 18.5 feet. He desires to lift at least 16 ft.

18.5 feet - 16 feet = 2.5 feet above Larry's current location.

Yes, Larry is able to draft 16 feet above his water source.

NWCG Latest Announcements

NWCG Equipment Technology Committee Releases New Equipment Bulletins

Date: September 27, 2024
Contact: Equipment Technology Committee

The Equipment Technology Committee (ETC) has released three new Equipment Bulletins:

  • ETC-EB-24-003 Diesel exhaust fluid (DEF) in fuel containers.
  • ETC-EB-24-004 Two-compartment fuel and oil container (Dolmar) unavailable in the United States (US) and reminders for upkeeping current inventories.
  • ETC-EB-24-005 Personal Protective Equipment (PPE): Inspection, Care, and Maintenance.

These bulletins remind field going personnel of important issues related to equipment for wildland firefighting efforts.

References:

NWCG Alerts

ETC-EB-24-003 Diesel exhaust fluid (DEF) in fuel containers

ETC-EB-24-004 Two-compartment fuel and oil container (Dolmar) unavailable in the United States (US) and reminders for upkeeping current inventories

ETC-EB-24-005 Personal Protective Equipment (PPE): Inspection, Care, and Maintenance

The Experiential Learning Subcommittee is looking for your feedback on Staff Rides

Date: September 20, 2024
Contact: Ashleigh D'Antonio and George Risko, Leadership Committee

The Experiential Learning Subcommittee needs to hear from the field about where the greatest need lies regarding staff rides and their accessibility.

  • Do you have an event you would like to turn into a learning experience?
  • Do you have a staff ride built, but are struggling to implement the delivery?
  • Do you need help building capacity?
  • What other ideas do you have to support experiential leadership training?

Fill out this short survey below to help us help you.

References:

Staff Rides: Feedback

Staff Rides

Updated NWCG Single Resource Casual Hire Information, PMS 934

Date: September 19, 2024
Contact: Incident Business Committee

The Incident Business Committee has updated the NWCG Single Resource Casual Hire Information, PMS 934. This update expands the provisions for hiring emergency personnel.

References:

NWCG Single Resource Casual Hire Information, PMS 934

IBC Memorandum 24-03

NWCG 2024 Spring/Summer Highlights

Date: September 13, 2024

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Welcome to our latest highlights from the National Wildfire Coordinating Group, where we explore the latest updates, insights, and efforts that develop interoperable wildland fire operations among federal, state, local, Tribal, and territorial partners.

The Performance Support Package, which for ABRO includes the Incident Position Standards and Next Generation Position Task Book were developed through the Incident Performance and Training Modernization (IPTM) effort. The Performance Support Package will support trainees, those qualified in the position, and evaluators.
 

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NASA JOINS NWCG!

The National Aeronautics and Space Administration (NASA) is officially an associate member of NWCG. As such, NASA is beginning to collaborate with wildland fire management agencies with the goal of increasing collaboration across agencies and leveraging NASA data, technology, and innovation for nation-wide efforts in wildland fire management. NASA has a rich history of research, development, and technology transfer in the areas of Earth science, space technologies, and aeronautics that support the NWCG mission.

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WWW.NWCG.GOV HAS A NEW LOOK AND DESIGN

The NWCG web team dedicated the past two years to making a significant upgrade to the www.nwcg.gov site. This upgrade involved a comprehensive redesign of over 7,700 web pages.

The modernization of NWCG’s website involved migrating to Drupal 10, a cutting—edge content management system, and leveraging Amazon Web Service GovCloud for secure and efficient hosting. These upgrades help ensure that the NWCG website remains current in content management practices, offering enhanced customization, improved performance, and an overall superior user experience.

NWCG Leadership Committee

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The Wildland Fire Leadership Development Program announced the Professional Reading Program’s 2024 list!

The years books include:

  • Young Men and Fire by Norman Maclean
  • The Wisdom of the Bullfrog by William H. McRaven
  • The Art of Clear Thinking by Hasard Lee
  • Emotional Agility by Susan David
  • Writing to Persuade by Trish Hall

Learn more at the NWCG Leadership Committee

INCIDENT PERFORMANCE AND TRAINING MODERNIZATION

In 2023, NWCG kicked off the Incident Performance and Training Modernization (IPTM) effort. A training system overhaul focused on developing a performance-based training system designed to shift training to on-the-job when appropriate.

Over the next five years, NWCG intends to analyze all positions within the NWCG Standards for Wildland Fire Position Qualifications, PMS 310-1. To date we are currently working on 30 incident positions, and planning for 20+ in calendar year 2025.

Subject Matter Experts from a variety of geographical areas and agencies recently completed the position analysis for 16 positions. From this analysis, Incident Positions Standards and a Next Generation Position Task Book will be developed for each position.

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Incident Performance and Training Modernization

NEXT GENERATION POSITION TASK BOOK

In April 2024, NWCG launched the new Next Generation Position Task Book (Next Gen PTB) which is a key component of the IPTM effort. This revised evaluation tool is designed to work in conjunction with the newly developed Incident Position Standards.

Major Next Gen PTB changes:

  • Structured to improve constructive conversations between evaluators and trainees.
  • Reference new Incident Position Standards.
  • Include only tasks required to be evaluated for successful performance.
  • Trainees will be rated on their performance vs. initialing whether a task was completed.
  • Must include written feedback when trainee does not meet the standard.
  • Will be position specific (no combined PTBs).
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NWCG’s training course catalog is now available on the Wildland Fire Learning Portal (WFLP).

To access the training course catalog, visit WFLP and either set up an account or login as a guest.