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Mitigating Dust on Helipads

DUSTABATEMENT PROJECT

Yuma, Arizona

16-24 January 2004

Final Report

Jeb S. Tingle, J. Andrew Harrison, and JohnF.Rushing

U.S. ARMYENGINEER RESEARCH AND DEVELOPMENT CENTER

Sponsored By:

U.S. MARINE CORPS SYSTEMS COMMAND

POC: Mr. Mike Farley

US Army Corps of Engineers

Engineer Research and Development Center

Evaluation of Expedient Methods for Mitigating Dust Dust on Helipads

Jeb S. Tingle, Andrew Harrison, and John F. Rushing

April 2004

Approved for public release; distribution is unlimited.

Executive Summary

The ERDC was tasked by the MCSC to develop two dust control systems, one for expeditionary use on FARPs and one for sustainment use on roads and other large area applications. The project consisted of the evaluation of various dust palliatives and application equipment under controlled laboratory conditions and during field tests. The products of this effort include equipment recommendations, palliative recommendations, and complete application guidance. This report addresses testing performed to evaluate commercial palliatives and palliative distribution systems for expeditionary use in constructing and maintaining FARP sites. Eighteen helipads were constructed at MCAS Yuma using both experimental and commercial palliatives for dust abatement. The application methods were principally topical (spray-on) and expeditionary in nature. Each helipad was subjected to CH-46 rotary-wing aircraft traffic, and selected helipads were subjected to CH-53 traffic. The helipads were evaluated based upon effectiveness in controlling dust, durability, FOD potential, and overall surface condition. Pertinent conclusions from the testing conducted are noted below and recommendations for selecting dust abatement methods and materials are provided in the following text.

Conclusions

The following conclusions were derived from the application and testing of selected dust palliatives from February to March 2004:

1. The commercial water trucks and distributors used to apply the products during the experiment were effective in agitating and distributing a uniform product. However, the cost and poor mobility of the vehicles make them unsuitable for extended military use.
2. The agricultural trailer with flotation tires demonstrated very good mobility, but did not include an agitation system for producing a consistent product and required a tow vehicle. In addition, the uniformity of product application was poor.
3. The two hydroseeders used during the experiment provided three methods of distribution, each useful in applying the products. The poor mobility of the hydroseeders due to the weight of the trailer-mounted systems reduced their overall effectiveness. However, the devices provided good agitation of the product and excellent uniformity of product distribution over the helipad. These devices provided a rapid means of topically distributing dust palliatives in an expeditionary environment.
4. The dust abatement vehicle (DAV) required the greatest time and manpower for product application of the methods evaluated. The DAV system required calibration of the drop spreader for dry palliative distribution due to the fineness of the dry powder. The system required additional manpower for hand raking the dry palliative into the helipad surface and guiding the vehicle during product distribution. The application of the water-polymer emulsion was time consuming due to the limitations of the spray nozzles used and the requirement to refill the tank. The DAV system was limited in the amount of water it could carry due to axle load limitations and will require additional assets such as an MTVR with water containers to provide the amount of water required for the Tri-PAM process.
5. The NRL experimental products and Soiltac® were effective in controlling the dust compared to the untreated helipad sections immediately after application with 3 days curing.
6. The following products performed well during testing of the helipads under rotary-wing traffic after 30 days: EnviroKleen®, Envirotac II®, Soiltac®, LDC®, PolyPlus®, PolyPlus 100®, and LDC®.
7. CO 110® and Tri-PAM were moderately effective in controlling the dust under the helicopter traffic after 30 days.
8. The Road Oyl®, NRL experimental products, and Dustac® applications were relatively ineffective in reducing the amount of airborne dust generated during rotary-wing aircraft operations after 30 days. These products were applied at very low application rates, which impacted their effectiveness. The NRL products and Road Oyl were effectively leached from the helipad during a 0.5-in. rainfall event and were ineffective in controlling dust in the subsequent test cycle.
9. Topical application of dust palliatives is typical of an expeditionary application where construction equipment is nonexistent or limited. Products may perform better using more rigorous construction processes and equipment.
10. Crust forming products tended to provide effective dust abatement under limited traffic, but light applications less than 0.5 gallons per square yard broke up during flight operations producing a potential FOD problem.
11. Tri-PAM, PolyPlus®, and PolyPlus 100® provided varying degrees of effectiveness controlled by the intimacy of the mixing process and the formation of polymer nodules binding the soil particles together. These products, polyacrylamides, are water absorbing and produced a very tacky surface following a 0.5-in. rainfall event.

Recommendations

Based on equipment testing completed by ERDC at the WES and field experience obtained during the exercise, the following recommendations are provided:

1. The palliative distribution system must be maneuverable in soft sand conditions. This requirement means the system must either be a self-propelled all wheel drive system, a trailer-mounted high floatation towable system that can be towed by a MTVR or TRAM, or a skid-mounted system that can be put on a high floatation trailer or on the back of the MTVR.
2. The distribution system should have multiple methods for applying dust palliatives. These methods include a spray hose system, a tower gun system, and a distribution bar system. Each system will have applications in the theater, including the distribution bar, which was evaluated at WES by ERDC personnel. The distribution bar will be extremely useful where site mobility permits its use and on larger areas such as roads and airfields.
3. The hydroseeder type equipment is recommended for the distribution system with the minimum requirements indicated in Table 15. However, the requirements noted in Table 15 should be evaluated for CH-53 and/or C-130 compatibility.
4. Due to the difficulty in securing repair/replacement parts for COTS equipment, it is recommended that two sets of nozzles, two sets of hose clamps and couplings, a hose repair kit, pump parts, and a small engine repair kit are included in the system procured. A toolbox should be included to store the extra parts.
5. Both the towed and skid-mounted application systems will require a means of transferring the palliatives from 275-gallon totes into the system. Thus, a small pump with 20 ft of 2-in. hose on each end is recommended for inclusion in the system to transfer palliative from shipping containers to the application equipment. Include an in-line quick-connect ball valve on the suction end of the hose.
6. The systems evaluated included rudimentary gages of remaining product. An improved system capable of measuring within 25 gallons of product should be included in the system selected. The ability to estimate the amount of product remaining is essential to achieving the desired application rate with limited material quantities.
7. The pulverizer systems commonly included on some hydroseeders are not necessary unless they also serve to agitate the material contained within the tank. As noted, a mechanical system is preferred due to the viscosity of the palliatives evaluated.
8. The frame of the trailer or skid-mounted system must be strong enough to support the weight of the loaded system and allow sling loading of the system for rotary-wing transport. The system should include adequate tie-down strong points for sling loading and mounting on an MTVR.
9. It is further recommended that a minimum of two 900-gallon towed systems and two 1,200-gallon skid-mounted systems be procured with the recommended amounts of product for immediate fielding. Feedback from designated units should be used to refine system parameters.
10. The COTS products were commonly shipped in 275-gallon totes. It is recommended that the products procured should be packaged in 275-gallon totes according to DoD shipping standards as a compromise between capacity and logistical footprint. The possibility of using 200-gallon totes should be pursued to minimize product waste.
11. Based upon the limited traffic applied to the helipads and pilot feedback, it is recommended that the USMC procure EnviroKleen® and apply the undiluted product “neat” at a minimum application rate of 0.36 gsy and a maximum application rate for sandy soils of 0.5 gsy. Gray water and salt water may be used for dilution.
12. Envirotac II®, Soiltac®, Soil-Sement®, and Liquid Dust Control® are recommended for use as dust palliatives where a firm surface crust is desired. The concentrated product (approximately 50% solids) should be diluted with 2 parts water to 1 part concentrate or a 2:1 dilution ratio. The diluted product should be applied at a minimum application rate of 0.65 gsy.
13. It is further recommended that the hydroseeder distribution systems and the dust palliatives recommended be fielded to units for evaluation and feedback. It is recommended that MCSC monitor the units’ feedback and lessons learned to develop long-term solutions for dust control on FARP sites.

This report includes the results of laboratory and field evaluations of selected dust abatement products and distribution equipment for rapid dust control of expeditionary helipads. The conclusions and recommendations provided in this report serve a guidance for rapidly mitigating dust generated by rotary-wing aircraft in an expeditionary environment with reduced logistical footprint products and equipment. The laboratory tests are described in Chapter 2, and the equipment evaluation is discussed in Chapter 3 of this report. A detailed description of the field tests conducted at MCAS Yuma on eighteen helipads is documented in Chapter 4. Conclusions and recommendations are presented in Chapter 5.

The full report is available on the JRAC Products Download page, then click on Dust Abatement Methods for Helipads