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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 others.
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. Separate volumes of the standards cover different categories of sprayers.
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 One of the FAO guidelines on minimum requirements covers portable sprayers which are carried in the hands or on the back of the operator and covers five principal types of sprayer:
LK - lever-operated knapsack; MK- motorized hydraulic knapsack;
Fogging machines are not yet included within the scope of the FAO guidelines.
For the purposes of these guidelines, a portable rotary atomizer sprayer consists of a spinning atomizer (usually a disc, or cup) onto which flows spray liquid, to produce spray droplets. The atomizer is driven by a small electric motor powered by a series of dry cells (torch batteries) or by rechargeable batteries carried either within the carrying handle, on the operator’s belt, or on a strap slung over the operator’s shoulder. Spray liquid flows onto the atomizer by gravity from a small bottle mounted on the spray head, and /or from a backpack or shoulder-slung tank.
It is important that buying agencies select the type of sprayer that is most appropriate for the intended use. The following notes will assist in the selection process.
Piston pumps are suitable for single-nozzle use and are preferable
to diaphragm pumps for multi-nozzle use where higher pressures are
required (up to 4 bar).
Motorized hydraulic knapsack sprayers
These units are a good option for use with multi-nozzle booms where prolonged pumping, even with a piston machine, is not practical.
Compression sprayers are necessary where field conditions make lever-operated machines impractical, for example on steep slopes and in dense crop foliage. They are also used in grain stores to treat wall surfaces. NB: The output from this type of sprayer declines during the pressure cycle unless a flow control valve is fitted to the sprayer.
Motorized mistblowers are used where the spray cloud needs to be
projected vertically to treat trees, but may also be used to spray
horizontally for row and bush crop spraying. They can also be adapted
for granule application. NB: Mistblowers are not recommended for herbicide
The provision of the correct nozzle (not applicable for rotary atomizers) enables safer and more efficient spraying. Appropriate nozzles should be supplied with the sprayer to cover the intended uses.
N.B. Adjustable multi-purpose nozzles are not recommended for use in crop protection. Consistent spray quality is difficult to reproduce and operators tend to adjust and touch these types of nozzle with bare hands when they are contaminated with pesticides.
High pressure and drift
One of the primary sources of operator hazard from hand-carried portable sprayers relates to high pressure (over 4 bar) with hydraulic nozzles, which can produce fine droplets that are prone to uncontrolled drift and inhalation. High pressures can also increase hazard through failure of sprayer components, resulting in major leakage of spray liquid. Therefore, a key criterion in appropriate sprayer design is the provision of systems of pressure control.
The minimum requirements specify the pressure limits recommended to minimize potential hazard without compromising spraying efficiency.
N.B. High-pressure spray guns and lances, which are commonly used in protected crops and in small-scale horticulture, produce an unacceptably high proportion of small droplets of a respirable size. The spray cloud produced by this type of equipment represents an unacceptable human hazard and drift potential and should not be used either for protected or for outdoor horticultural or agricultural crops.
Using the guidelines on minimum requirements
For the purposes of defining these guidelines, portable sprayers can be divided into several “component modules” (see Figure 1). Within each module, especially in relation to safety, with relatively few exceptions the functional requirements are the same for all sprayer types.
The guidelines on minimum requirements do not aim to provide precise quality requirements and test procedures. These are addressed in the companion guideline in this series. Guidelines on standards for agricultural pesticide sprayers and related test procedures. The guidelines on minimum requirements 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.
1. Module 1 - GENERAL REQUIREMENTSFor LK, MK, CS, MB, RA
Portable (operator–carried) pesticide sprayers for agriculture 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.
1.1 Total mass when filled to the manufacturer’s recommended maximum capacity should not exceed 25 Kg.
For RA, the following are acceptable guidelines for the division of the total mass.
1.2 The sprayer should not leak.
1.3 The sprayer should be easy to clean thoroughly both inside and out. Rough surfaces and awkward recesses should be avoided.
1.4 The outer surfaces of the sprayer should not trap nor retain spray liquid.
1.5 There should be no sharp edges, abrasive areas or unnecessary projections, which could injure the operator.
1.6 The sprayer should incorporate a conveniently located handle to enable it to be safely carried when not in use. (LK, MK, CS,).
1.7 The sprayer should be stable and stand upright on slopes up to 15% (1 in 7), irrespective of the amount of liquid in the tank. (LK, MK, CS, MB.)
1.8 Servicing, maintenance, adjustment and cleaning of all sprayer components should be easily accomplished without needing special tools (i.e. tools specifically designed for the sprayer).
1.9 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.
1.10 All pressure and flow control devices should be adjustable from outside the spray tank.
1.11 A safety device should be incorporated into the sprayer to prevent the maximum pressure exceeding 5 bar (LK, MK,) and 6 bar (CS) in any part of the sprayer and vented liquid should be discharged inside the tank.
1.12 The manufacturer should provide with the sprayer a clear, simple, illustrated manual in English, French or Spanish and an accepted commercial language in a specific market for which the sprayer is being evaluated.
1.13 The manual should contain procedures for:
It should provide information on:
1.14 The manufacturer should also provide written assurance in the sprayer manual that:
2. Module 2 - TANKFor LK, MK, MB, RA
2.1 For RA in this module, the tank refers to any container that is hand-held, carried on straps on the operator’s back or slung on a strap over a shoulder, which is used to contain the spray liquid to be applied through a rotary atomizer.
2.2 The tank should be clearly and durably marked with:
2.3 During filling, with the strainer fitted (see Section 2.4) the level of liquid in the tank should be clearly visible as it approaches the nominal maximum filling level.
2.4 The tank should include a strainer, located in the fill opening to filter the water or spray solution as it enters the tank.
2.5 The strainer should be easy to remove and fit with gloved hands. For this and for other checks, where gloves are recommended they should have a minimum thickness of 0.5 mm.
2.6 The strainer should have a mesh aperture size no greater than 1.0 mm.
2.7 The strainer mesh should be securely fitted to, or form part of, the strainer body.
2.8 The strainer should be close fitting and permit safe, easy filling from a non- profiled container (i.e. one without a lip or spout) at a rate of 25 litres per minute without overflowing, splashing or lifting from its seat.
As a guide: it is suggested that the strainer should be recessed
into the fill opening, which should be no less than 100 mm across
the smallest dimension.
2.9 The tank fill opening should be sealed with a lid that can be opened and securely closed with gloved hands and without tools.
2.10 When closed, the lid should not collect spray liquid.
2.11 Either the lid or the tank should have a ventilation valve.
2.12 When a sprayer includes an agitator device; it should move freely, should not catch on other parts of the sprayer and should be easily removed and refitted with gloved hands.
For Compression sprayers (CS)
2.13 The tank should have a minimum capacity of 5 litres.
2.14 The tank should be clearly and durably marked to show the nominal (manufacturer’s recommended) maximum filling level, which should be equivalent to no more than 75% of the total volume of the tank.
2.15 When during filling the spray liquid level in the tank is not clearly visible, the manufacturer’s recommended maximum volume in litres should be clearly marked on the tank and included in the sprayer manual.
2.16 A funnel with an integral strainer should be supplied with the sprayer, to filter the water or spray solution as it enters the tank.
2.17 The funnel strainer should have a mesh aperture size no greater than 1.0 mm.
2.18 The funnel strainer mesh should be securely fitted to, or form part of, the funnel body.
2.19 The funnel should permit safe, easy filling from a non-profiled container (i.e. one 1.1 without a lip or spout) at a rate of 10 litres per minute, without overflowing or splashing
2.20 The tank fill opening should be sealed with a tank lid, which can be opened and securely closed with gloved hands without tools.
2.21 The tank should be fitted with a pressure-indicating device.
2.22 The tank should be fitted with a pressure relief /safety valve to prevent the pressure in the tank from exceeding 6 bar.
2.23 The tank should be fitted with a pressure release valve that operates easily with gloved hands.
2.24 After spraying, it should not be possible to remove the lid (or pump) before the residual pressure in the tank has been released.
2.25 Threaded fittings to the pressurised parts of the tank with a diameter greater than 13 mm should include a channel to ensure that the pressure in the tank is released before the lid (or pump) can be removed.
3. Module 3 - LANCE ASSEMBLY AND SPRAY HOSE (For LK, MK, CS)AIR TUBE AND SPRAY HOSE (For MB)
3.1 Spray hoses, when bent through 180 degrees at temperatures up to 30°C, should not kink (flatten).
3.2 Hose connections should be easily adjustable and removable with gloved hands and should not leak when reconnected.
3.3 Spray hoses should be of sufficient length to allow free movement and appropriate positioning of the lance for spraying.
3.4 The minimum length of the lance from the front of the hand trigger
grip to the nozzle should be 500 mm. For MB the length of the air
tube from the on/off lever to the air outlet should be no less than
3.6 The lance should be fitted with a trigger-type on/off valve, which can be locked in the “off” position. For MB the liquid supply line to the nozzle should incorporate an on/off valve.
3.7 The length of a trigger valve lever measured from the pivot point should be no less than 100 mm.
3.8 The lance assembly (LK, MK, CS) should include a removable filter with a mesh aperture size not exceeding 0.3 mm that is easy to install and remove with gloved hands.
3.9 The removable filter in the lance assembly (see Section 3.8) should be located upstream of the trigger valve.
3.10 Interchangeable but not adjustable nozzles (LK, MK, CS) or restrictors (MB) should be supplied with the sprayer.
3.11 The maximum operating pressure at the nozzle should not exceed 4 bar (LK, MK, CS).
3.12 When a pressure indicator is included, it should be downstream of the on/off valve (LK, MK, CS).
4. Module 4 - SPRAYER ASSEMBLY for RA (spray- head, bottle, handle)
4.1 In all recommended working positions, the spray head should be a minimum of 500 mm from all parts of the operator’s body to ensure that there is no direct contamination of the operator from the spray droplets.
4.2 To control the rate of flow of the spray liquid, the sprayer should be supplied with colour-coded, interchangeable restrictors that can be changed without special tools (i.e. without tools developed specifically for the sprayer).
4.3 A shield should be supplied with the sprayer to protect the atomizer from physical damage when it is not in use.
4.4 When the spray liquid to the atomizer is supplied solely from the bottle on the spray head (i.e. not re-filled from a spray tank) a funnel should be provided with the sprayer.
4.5 The funnel should enable the bottle to be filled easily from a non-profiled container (i.e. one without a lip or spout, which will normally be a pesticide container) without spilling or splashing, at a rate of 5 litres per minute.
5. Module 5 - STRAPS AND PADDINGFor LK, MK, CS, MB, RA
5.1 Straps and fixings should be strong and durable.
5.2 The manufacturer should provide written assurance in the sprayer manual that: straps and padding are of non-absorbent material straps and padding resist undue deterioration from contact with approved pesticide formulations.
5.3 An LK sprayer should be equipped with a load-bearing waist strap.
5.4 The load-bearing part of shoulder straps should be a minimum
of 50 mm wide.
5.7 Straps should be equipped with quick release catches that function efficiently when the tank (LK, MK, MB, RA) is full and in the working position on the operator’s back.
5.8 Back-carried tanks when in the working position should be comfortable for the operator, either through the profile of the tank or through the provision of a back-frame.
6. Module 6 - POWER SOURCE
Manual lever and pump – LK
6.1 The lever to operate the pump should be a minimum of 400 mm long and should have an arc of movement not exceeding 400 mm.
6.2 The lever should function for both left and right-handed use.
6.3 The end of the lever should be firmly and durably equipped with a handgrip with a minimum sectional dimension of 25 mm and a minimum length of 100 mm.
6.4 To achieve the maximum recommended flow rates and operating pressures, the pump should operate within the range of 20-30 lever strokes per minute.
6.5 At the maximum recommended flow rate, the pressure, measured immediately upstream of the nozzle, should not deviate by more than ± 10 %.
Manual plunger and pump – CS
6.6 When the pump is manual, it should produce a pressure of 4 bar in the spray tank on completion of not more than 60 complete plunger strokes with the tank filled to nominal capacity.
6.7 Where the pump is located inside the spray tank, it should meet the following requirements.
6.8 The sprayer manufacturer should provide written assurance in the sprayer manual that:
Engine – MK and MB
6.9 The throttle lever must remain firmly fixed in any pre-set position during operation.
6.10 The engine should have an instant “cut out” mechanism that is readily accessible to the operator when the sprayer is in the working position on his/her back.
6.11 The engine should have a safe, robust starting mechanism.
6.13 The engine should be isolated from the carrying frame by anti-vibration mountings.
6.14 The engine should be robustly protected against accidental physical damage.
6.15 The fuel tank and the fuel on/off valve should be positioned to minimise the risk of fuel spilling onto the engine.
6.16 The fuel on/off valve should be close to the fuel tank outlet and easily accessible to the operator when the sprayer is in the working position.
6.17 An easily serviceable fuel filter should be located in the line between the tank and the carburettor.
6.18 An easily replaceable air filter should be located directly on the carburettor intake.
6.19 Carburettor adjusting screws should be readily accessible without needing to remove parts or use special tools (i.e. tools specifically designed for the sprayer).
6.20 The noise level at the ear of the operator should not exceed 85 dB.
6.21 The fuel tank should have sufficient capacity for a minimum of one hour of continuous operation.
6.22 When a two-stroke engine is present, the fuel tank should be durably marked with the required fuel/oil ratio.
6.23 All moving parts should be well shielded to prevent injury.
Engine-driven pump – MK, (or MB)
6.24 Where the engine drives a pump by a pulley or gearing system, special care should be taken to fit adequate guards so that no moving parts are exposed.
Engine-driven fan – MB
6.25 Casing measuring no more than 45 cm diameter should protect the fan.
6.26 The inlet to the fan should be equipped with a guard with a minimum mesh- aperture size of 5 mm and a maximum size of 10 mm.
7. Module 7 - ATOMIZERS (Spray generating devices)
It is the responsibility of the sprayer manufacturer to comply with the following requirements for atomizers supplied with or recommended for the sprayer even though the information may originate from another manufacturer, who specialises in nozzles or rotary atomizers.
Hydraulic nozzles – LK, MK, CS
7.1 Nozzles supplied with or recommended for a sprayer should be manufactured to international standards (ISO).
7.2 The sprayer manufacturer should include in the sprayer manual, information on:
7.3 For flat fan nozzles, the nozzle support system should include a method of ensuring correct orientation of the nozzle within the holder.
Rotary atomizers - RA
7.4 The sprayer manufacturer should include in the sprayer manual information on:
7.5 Output from any 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.
Shear nozzles – MB
7.6 Where mistblowers are fitted with shear nozzles, the sprayer manufacturer should include in the sprayer manual, information on the recommended range of flow rates for different crop targets.