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© FAO 2001
C O N T E N T S
These guidelines were prepared by T. L. Wiles and D. G. Sharp, of T L Wiles and Associates Limited, Chichester, UK with the assistance of Professor G. A. Matthews of IPARC, Imperial College at Silwood Park, University of London. The valuable contributions and comments of the many international experts from both the public and private sectors are also acknowledged.
Safety and quality standards for agricultural pesticide sprayers do not exist in all FAO member countries and existing international standards for this type of equipment are often inappropriate for many member countries. Since 1995 FAO-AGSE has worked on the formulation of guidelines to improve the safety and efficiency of the most commonly used types of spray equipment.
The FAO guidelines on standards are based on existing international, European and national standards and other published references. They also draw on the in-depth knowledge and experience of international sprayer standards of the experts assigned to the project and on the authors’ experience of pesticide application in the developing world.
The first versions of the FAO guidelines on pesticide application equipment were approved for publication in May 1997 by; the FAO Panel of Experts on Pesticide Specifications, Registration Requirements, Application Standards and Prior Informed Consent; and the FAO Panel of Experts on Agricultural Engineering.
This publication is the first revision of these guidelines, which incorporate comments and suggestions received from member states and new international developments since 1997. There are two guidelines; the first covers minimum requirements and the second covers more precise standards and test procedures to determine compliance.
An important objective of the guidelines on minimum requirements is to assist FAO and other agencies to ensure that sprayers purchased are safe to users and to the environment as well as being efficient and durable in operation. Price will always play an important part in purchase decisions on equipment but even the cheapest sprayer models should meet minimum standards of safety and durability.
The FAO minimum requirements take into account sprayers that are already on the market, many of which already meet the requirements. The prime objective therefore is that member countries should adopt them immediately, to begin to eliminate substandard and unsafe sprayers from national markets and ultimately from the international scene.
The guidelines on minimum requirements are presented in separate
volumes covering different categories of spray equipment, such as
the principal types of portable (operator-carried) sprayers, including
rotary atomizers, vehicle-mounted and trailed (tractor) sprayers and
Guidelines on standards and test procedures
The guidelines on standards are more demanding than the minimum requirements and provide more precise safety targets for spray equipment. They consist of detailed specifications and requirements, supported by test procedures to measure compliance with the FAO standard, for the major types of agricultural pesticide sprayers manufactured or used in FAO member countries. These standards reflect current manufacturing practice, other national and international standards and the practical reality in the field in member states.
The aim of both the minimum requirements and the standards guidelines is to provide manufacturers and governments with a practical and consistent quality assurance system. Each member country can then decide on the form and speed of introduction of the respective guidelines into national practice and into legislation where appropriate.
The entire series consists of the following other guidelines:
Guidelines on procedures for the registration, certification and testing of new pesticide application equipment;
These guidelines outline a further way by which governments can influence pesticide safety by controlling the quality of the pesticide application equipment manufactured in or imported into the country. By incorporating into national legislation, a requirement for manufacturers and importers to declare that application equipment meets standard of safety and durability, it should be possible to gradually reduce and eventually eliminate sub-standard equipment from the market.
Guidelines on the organization of schemes for testing and certification of agricultural pesticide sprayers in use
This publication covers the testing and certification of the sprayers currently applying pesticides on commercial farms. They address an urgent need in many countries to ensure that where pesticides are used in crop production, they are applied through equipment, which is safe and fully functional. The issue applies to both large, field crop and orchard sprayers as well as operator-carried equipment.
Guidelines on the organization and operation of training schemes and certification procedures for operators of pesticide application equipment.
These guidelines consider the training, testing and certification of those who actually operate pesticide application equipment. Even the most well designed and maintained sprayer can do immeasurable damage in the hands of an unskilled operator and the importance of these guidelines should not be underestimated.
A further two guidelines in the series cover application of pesticides
using aircraft and field crop sprayers and tree and bush crop sprayers:
These guidelines have been prepared to offer practical help and guidance to all those involved in using pesticides for food and fibre production or in public health programmes. They cover the main terrestrial and aerial spray application techniques.
Volume two of the FAO guidelines on minimum requirements covers vehicle-mounted, trailed and self-propelled field crop, orchard and plantation sprayers. These types of sprayer fall into two distinct groups according to the height and architecture of the crop/target to be sprayed:
Tree and bush crop sprayers
High pressure and drift
One of the primary sources of potential hazard from terrestrial vehicle sprayers is high pressure that can produce fine droplets, which are prone to drift and inhalation. High pressure can also increase hazard through component failure leading to major leakage of spray liquid. Therefore, a key criterion in sprayer design is the provision of systems for pressure control within the sprayer and at the nozzle. These guidelines specify the functional requirements for sprayers and the pressure limits recommended to minimize hazards without compromising spraying efficiency.
Using the guidelines on minimum requirements
For the purposes of determining these minimum requirements, sprayers are divided into several “component modules” (Figure 2). Within each module the functional requirements, especially in relation to safety, are defined and presented as a simple series of numbered clauses (sections).
The minimum requirements do not aim to provide precise quality requirements and test procedures. These issues are addressed in the companion guideline of this series: Guidelines on standards for agricultural pesticide sprayers and related test procedures. The aim of the guideline on minimum requirements is to provide a practical aid to assist purchasing and other agencies to avoid buying or approving sprayers with quality and design limitations, which could compromise operator and environmental safety.
The modular format used in this document was developed by the authors as the basis of a guide to assist FAO and other buying agencies in the selection of crop sprayers: FAO Basic Guidelines for the Selection of Agricultural Pesticide Sprayers, June 1995.
Each module relates to a major component or a functional group of components from which consistent specifications for complete spraying machines can be compiled. The various modules for vehicle-mounted and trailed sprayers, which are generally referred to as “tractor sprayers”, are shown in Figure 2.
The following requirements therefore apply to all terrestrial agricultural spraying equipment, which is operated in conjunction with a tractor, mounted on a purpose built chassis unit or within a multi-purpose agricultural/horticultural vehicle. Throughout this document, for convenience, these types of spraying equipment are referred to as “the sprayer”.
* required for sprayers with tank volumes over 1000 litres
1. Module 1 - GENERAL REQUIREMENTS
Sprayers should be safe, reliable and capable of working efficiently under practical field conditions.
They should be robustly constructed from strong, durable materials which will not obviously be prone to undue deterioration during field use, thereby adversely affecting safety and lowering efficiency due to corrosion, rust, distortion or premature wear.
To meet the FAO minimum standard, a sprayer should comply with the following requirements.
1.1 The sprayer unit should be securely attached to the vehicle system.
1.2 All shaft drives should be adequately guarded so that no moving parts are exposed.
1.3 Potential trapping points, which could cause physical injury e.g. created by the boom folding or height adjustment mechanism, should be fitted with guards. In positions where guards are not practical, the sprayer should be fitted with appropriate, clear warning signs.
1.4 All handles, grips or handholds should be at least 300 mm from any hinged joint.
1.5 Hydraulic oil connections should be via “snap-fit” connector systems.
1.6 Ideally sprayers should be fitted with a closed transfer system, however, where filling of either water or chemical is manual, it should be possible for the operator to add the chemical or water to the tank either standing on the ground or on a purpose-built platform with a minimum floor area of 0.5 m2.
1.7 Platforms, should be made from anti-slip flooring and have guardrails.
1.8 Reach distances should not exceed 1.0 m vertically from the ground or platform and there should be no obstructions around the fill area.
1.9 The filling system for the spray tank(s) should permit safe, easy filling at the manufacturer’s recommended maximum rate without overflowing or splashing.
1.10 The sprayer should not leak under working conditions at recommended pressures and flow rates.
1.11 The sprayer should be easy to clean thoroughly both inside and out. Rough surfaces and awkward recesses, should be avoided.
1.12 The outer surfaces of the sprayer should not trap or retain spray liquid.
1.13 There should be no sharp edges, abrasive areas or unnecessary projections, which could injure the operator.
1.14 Trailed sprayers, even when disconnected from the towing vehicle, should be stable and remain upright when positioned on a 15% (1 in 7) slope in any direction, irrespective of the amount of liquid in the tank(s).
1.15 Adjustments to the sprayer, routine maintenance, drainage and cleaning should be easily carried out without needing special tools (i.e. tools specifically designed for the sprayer).
1.16 The manufacturer should provide with the sprayer, a clear, simple, illustrated, instruction manual in English, French or Spanish and in an accepted commercial language in a specific market for which the sprayer is being evaluated.
1.17 The manual should contain procedures for:
1.18 The manual should also provide written assurance that:
1.19 To facilitate the accurate identification of replacement parts,
the sprayer should be clearly and durably marked to indicate; the
manufacturer’s name and address and the sprayer name and model.
2. Module 2 - TANKS
There are often several tanks, or similar structures fitted to a sprayer.
To comply with the FAO standard, a sprayer should be equipped with:
Sprayers with a spray tank (s) capacity of 1000 litres or more require:
Spray tank(s), lid and strainer
2.1 Spray tank(s) should be mechanically durable.
2.2 Fill openings should be closed with tight-sealing lids that are securely attached to the tank.
2.3 Lids should be fitted with positive, mechanical closure systems, which enable them to be opened and closed with gloved hands. For this and for other checks, where gloves are recommended they should have a minimum thickness of 0.5 mm.
2.4 Fill openings greater than 400 mm in diameter or, if rectangular, greater than 400 mm x 300 mm, should be fitted with a grating, which cannot be removed without using tools.
2.5 Fill openings should be fitted with a strainer with a maximum mesh aperture size of 1.0 mm.
2.6 Strainers should be easy to remove and fit with gloved hands
2.8 Tanks should be clearly and durably marked with the nominal (manufacturer’s recommended maximum) filling level, which should not exceed 95% of the total volume of the tank.
2.9 The sprayer should be fitted with a means of indicating the level of liquid in the spray tank(s), with a scale interval of no more than 20% of the nominal volume of the tank(s).
2.10 Liquid level indicator(s) should be clearly visible to the sprayer operator from the normal working (spraying and filling) positions.
2.11 Spray tanks should incorporate a safe and convenient system to enable the drained liquid to be collected or discharged for safe disposal.
2.12 The spray tank should be fitted with an agitation system except where the sprayer is designed to operate exclusively with control systems in which the diluent (water) and the concentrated pesticide are controlled separately.
Personal washing tank
2.13 The personal washing tank (the tank) and associated plumbing
circuit should contain clean water only and should be fully independent
of the main sprayer circuits, which contain chemical solution.
2.15 The tank should be securely fixed to the sprayer.
2.16 The tank should be constructed from materials that will not rust or corrode thereby contaminating the water.
2.17 Sprayers with tank capacities of 1000 litres or more must be
fitted with an induction hopper that complies with this module.
An induction hopper should satisfy the following requirements.
2.19 The hopper should efficiently handle all commonly used pesticide
formulation, liquids, powders, granules, soluble sachets and bags.
This assurance, together with recommended procedures for use, should
be included in the sprayer manual.
2.21 The hopper should be clearly and durably marked to show the recommended maximum filling level, which should be no more than 95% of the total volume of the hopper.
2.22 The hopper should be fitted with a lid, which is securely attached to the hopper.
2.23 The fill hole should have a minimum dimension of 250 mm.
2.24 The fill hole should be between 0.5 and 1.0 m from the ground.
2.25 There should be a minimum clearance zone (i.e. an area free
from obstacles) of 500 mm around the hopper.
2.27 Parts of the hopper that come into constant direct contact with the spray liquid should be made from non-absorbent materials, which are suitable for use with approved pesticide formulations. This assurance should be included in the sprayer manual.
2.28 Instructions related to the operation of the induction hopper, should be clearly and durably marked on the sprayer or hopper.
2.29 The sprayer manual should also include:
Flushing / rinse tank
2.30 Sprayers with spray tank capacities of 1000 litres or more must be equipped with a flushing tank that complies with this module.
These tanks are required to provide clean water to clean the sprayer tanks and the plumbing circuits on the sprayer that contain pesticide solution.
2.31 The liquid circuits on the sprayer should be designed to ensure that it is not possible to use liquid from the flushing/rinse tank for personal washing.
2.32 The volume of the flushing/rinse tank should be a minimum of 10% of the volume of the main sprayer tank(s).
3. Module 3 - PUMP
3.1 When operating at its recommended rotational speed, the pump should have sufficient capacity to supply the boom, fitted with the largest nozzle size and operated at 20% above the manufacturer’s maximum recommended working pressure.
3.2 It should be possible to remove the pump from the sprayer without draining the tank(s).
3.3 The pump should be permanently marked with:
4. Module 4 - FILTERS AND HOSES
4.1 When the sprayer is fitted with a pump, which operates with valves,
there should be a filter on the suction side of the pump with a maximum
mesh aperture size of 0.5 mm.
4.3 Filters should be readily accessible for cleaning and maintenance.
4.4 Filters should be easy to clean without needing to empty the sprayer tank(s).
4.5 Hoses fitted to the sprayer should be durably marked to indicate
their rated pressure, which should be equal to or greater than the
maximum operating pressure of the sprayer, plus 20%.
4.8 Hoses should be fitted to the sprayer so that they are not bent sharply (kinked), which could reduce the effective bore of the hose.
4.9 Hose connections should be easily adjustable and removable using gloved hands without needing special tools (i.e. tools specifically designed for the sprayer) and should not leak when reconnected.
5. Module 5 - CONTROL VALVES AND GAUGES
5.1 All sprayers should be fitted with a pressure safety device to prevent the pressure in any part of the circuit exceeding the maximum operating pressure by more than 20%.
5.2 The pressure safety device should ensure that all vented liquid flows are discharged into the main tank.
5.3 The boom should be fitted with spray lines and valves so that the supply of liquid to each boom section can be controlled independently.
5.4 There should be a single master control valve for turning on/off the supply to all boom sections.
5.5 “Anti-drip” valves should be incorporated in the sprayer circuit to minimise the loss of spray liquid from nozzles once the liquid supply to a boom section has been turned off. The maximum leakage from a nozzle should not exceed 2 ml in a 5-minute period, commencing 8 seconds after the supply to the boom section has been switched off.
5.6 A fail-safe system should be incorporated into the sprayer to prevent back-flow by siphoning while the spray and rinse tanks are being filled.
5.7 Sprayers designed to operate with hydraulic pressure nozzles should be fitted with a pressure gauge, which is clearly visible to the operator from the driving position. In the case of an analogue dial, this should have a minimum diameter of:
Other forms of display, e.g. digital readouts, should be clearly visible from the operating position
5.8 The pressure gauge indicator should provide a stable reading.
5.9 The housing of pressure gauges should be isolated from the spray liquid so that, in the event of failure leading to leakage, the operator is not contaminated.
6. Module 6 - BOOMS
6.1 Booms should be rigidly constructed so that all nozzles along a boom are supported at the same height.
6.2 A minimum range of height adjustment of one metre should be possible.
6.3 The mechanism for height adjustment should incorporate a fail-safe feature so that in the event of failure of the mechanism, the boom height will not change by more than 0.2 m.
6.4 Where a manually operated system for boom height adjustment is used, it should be of a self-arresting type.
6.5 For powered height adjustment systems the sprayer should be fitted with either:
6.6 Boom height settings of less than 0.5 m should only be possible by manually overriding the 0.5m stop control.
6.7 All height adjustment systems should be fitted with a locking device.
6.8 Booms more than 10 m wide should incorporate a mechanism, which will isolate the boom from the movements of the spray vehicle, i.e. they should be equipped with a boom suspension system.
6.9 The boom should also be isolated from the yawing movements of
the vehicle. With the boom extended and the machine stationary, it
should be possible to displace the boom tip by a horizontal distance
of 20 mm for each 1m of boom width, without distorting the boom structure.
6.11 When folded in transport positions, the boom sections should not:
6.12 The sprayer should be fitted with a mechanism to lock the boom sections securely in the transport position.
6.13 To minimise the risk of contact with overhead power cables during the folding operation, no part of the sprayer or boom should at any time, extend to a height of more than 5.0 m above the ground.
6.14 Booms, which when folded extend to a height of more than 3.5 m above the ground, should be fitted with a warning sign pointing out the potential hazard from overhead cables. This sign should be easily understood and clearly visible to the operator from the working (driving/spraying) position.
6.15 The design of the boom should ensure protection of the nozzles from damage from contact with the ground.
6.16 Boom sprayers designed to operate with air-assistance are required to meet all the standard requirements in 6.1 to 6.15. In addition, manufacturers of this type of sprayer should include in the sprayer manual:
6.17 When the sprayer is equipped with a fan to generate air, it should comply with the requirements in Module 7.
Tree and bush crops
6.18 The spray boom (delivery arc) should allow:
6.19 The boom should be rigidly attached to the sprayer.
6.20 Where the boom is intended to operate in different positions in relation to the air stream, clear, detailed instructions should be included in the sprayer manual describing the settings for effective operation in different crop and weather conditions.
6.21 When the boom can be used without air assistance, detailed instructions should be included in the sprayer manual on how to set up the sprayer for effective operation for different crop targets and conditions.
7. Module 7 - FANS (for air-assisted spraying)
7.1 The drive to the fan unit should be capable of disconnection without affecting the mechanism for circulation and agitation of liquid in the sprayer.
7.2 The inlet to the fan should be designed and positioned so that debris is not drawn into the fan, even at the highest operational speed.
7.3 The lowest point of the fan inlet must be at least 25 cm above the ground.
7.4 The fan should be equipped with a permanent guard with a minimum mesh aperture size of 5 mm and a maximum size of 10 mm.
7.5 The noise level, when the sprayer is operated at the maximum airflow, should not exceed 85 dB at the operator’s ear.
8. Module 8 - ATOMIZERS (spray generating devices)
It is the responsibility of the sprayer manufacturer to comply with the following requirements for nozzles and rotary atomizers supplied with or recommended for the sprayer even though the information may originate from another manufacturer, who specialises in nozzles or rotary atomizers.
8.1 The sprayer manufacturer should include in the sprayer manual, information on:
8.2 The sprayer manufacturer should provide assurance in the sprayer manual that nozzles supplied with or recommended for the sprayer are manufactured to international standards e.g. International Standards Organisation (ISO).
8.3 Output from any single nozzle or between nozzles with the same identity code i.e. which claim to have the same characteristics, should not differ by more than ±10 percent from the specified output at any recommended pressure.
8.4 For flat fan nozzles, the nozzle support system should include a method of ensuring correct orientation of the nozzle within the holder.
These devices create a spray within a nozzle body via pressurized supplies of both liquid and air.
8.5 Sprayers fitted with twin fluid nozzles should be equipped with
separate pressure control valves and gauges to control the liquid
and air supplies respectively.
8.7 Output from any single nozzle or between nozzles with the same identity code i.e. which claim to have the same characteristics, should not differ by more than ±10 percent from the specified output at any recommended pressure.
8.8 The sprayer manufacturer should provide in the sprayer manual, information on:
8.9 Output from a single rotary atomizer restrictor or between restrictors with the same identity code i.e. which claim to have the same characteristics, should not differ by more than ± 10 % from the nominal output.
8.10 The atomizers should be capable of 50 hours of operation at maximum operating speed without loss of performance or needing maintenance. The manufacturer should provide written assurance of this in the sprayer manual.
9. Module 9 - PROTECTIVE CLOTHING STORAGE COMPARTMENTS
9.1 Sprayers with tank capacities of 1000 litres or more, must be equipped with protective clothing storage compartments, which comply with this module.
9.2 The sprayer should be equipped with two compartments; one for clean clothes and the other for contaminated clothes.
9.3 The compartments should be located on the sprayer as far away as possible from the point of chemical loading.
9.4 The minimum internal dimensions of the compartments should be 450 mm x 450 mm x 300 mm.
9.5 The compartments should be clearly and durably marked: