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E001: Cold Rooms, Freezer Rooms and Related Equipment

E001: Cold Rooms, Freezer Rooms and Related Equipment

All the equipment included in the E001 category is manufactured to meet the specific needs of national immunization programmes. End-users must specify their requirements for the procurement phase. They must also select or build the space where the equipment will be housed and must provide the necessary electrical power supply, wiring and other services to which the equipment will be connected by the installer. Once received on-site, the equipment must be assembled and commissioned by a competent installer.

Details regarding the products included in each sub-category of E001 as well as guidelines, performance specifications and verification protocols for this category, can be accessed through the drop-down sections below.

A building that houses a cold room or freezer room needs to be site-ready and accessible to delivery vehicles. Details around adequate ventilation, electricity supply, among other key considerations, can be found in the pre-procurement checklist provided in the UNICEF Cold Chain Support Package.

The principle steps involved in buying and commissioning a cold room are:

  1. Establish net vaccine capacity: It is essential to calculate accurately the net vaccine capacity of the cold room(s) and freezer room(s), taking account of future vaccine introductions. WHO tools are available to help establish the required capacity of the store. Orders should not be made on the basis of gross capacity — for example a 40 m³ room — without verifying usable net capacity with the supplier.
  2. Decide location: Select the spaces(s) in which the equipment is to be installed. Building selection and preparation guidance is provided in the WHO Guideline for establishing or improving primary and intermediate vaccine stores.
  3. Shortlist suppliers: UNICEF Supply Division has long-term purchase agreements with prequalified cold room companies. If the cold room is not being purchased through UNICEF, a tender long list should be prepared. This should preferably include the companies of prequalified products listed in the UNICEF Supply Catalogue.
  4. Prepare and invite tenders: Prepare tender documentation using the PQS performance specification E001/CR/FR-01.4 and verification protocol E001/CR/FR01-VP1.4. If required, tenders should be invited for a standby generator and voltage stabilizer at the same time. Specific guidance on specifying and buying generators is provided in section E001.2. Guidance on heavy duty voltage stabilizers is provided in E001.3.
  5. Prepare the site: The space for the cold room should be prepared in accordance with the supplier's requirements and the WHO Guideline for establishing or improving primary and intermediate vaccine stores.
  6. Supervise: Care should be taken to supervise the installation and oversee commissioning and user training.
  7. Monitor: Check the performance of the equipment in use and the effectiveness of the maintenance agreement should be monitored.
  8. Maintain: Ensure that the temperature monitoring equipment is recalibrated annually. For additional guidance on maintenance refer to:


     

Prepare tender documentation using PQS performance specification E001/CR/FR-01.4 and verification protocol E001/CR/FR01-VP1.4. If required, tenders should be invited for a standby generator and voltage stabilizer at the same time. Specific guidance on specifying and buying generators is provided in the drop-down section below (E001.2), as is guidance on heavy duty voltage stabilizers (E001.3).

While WHO and UNICEF recommend that all primary vaccine stores should be fitted with a standby generator with automatic start up, regardless of the reliability of the mains power supply (refer to WHO also recommends that product users also consider installing standby generators in the following situations:

  • at large intermediate vaccine stores, equipped with cold rooms

  • at other sub-national stores where the mains power supply is sufficiently unreliable to compromise the performance of ice-lined refrigerators, even when they are fitted with voltage stabilizers..

In all other situations, if power cuts are a chronic problem, review alternative solutions such as ice-lined appliances fitted with voltage stabilizers and photovoltaic equipment. The decision to purchase a standby generator should not be taken lightly as it involves a relatively high upfront investment as well as significant maintenance and training costs.

The guidance notes in this section are for background information only. They are intended to be used to brief a professional engineer and/or to communicate with system suppliers and installers. Wherever possible, the generator should be supplied by the cold room/freezer room manufacturer as part of a comprehensive package (see E001.1). In all other cases, seek the advice of a qualified electrical engineer. In situations where an engineer is not available, refer to a reliable technical source such as Engineering in Emergencies — A Practical Guide for Relief Workers (ISBN-13: 978-1853395215 and ISBN-10: 1853395218).

E001.2.1: Specifying the generator

The generator house: The size of a standby generator is determined by the rated load of the equipment to which it is connected. The figure below shows the layout of a typical generator house.

A typical generator house

The generator house should have a concrete floor slab. Install ventilation openings near the bottom of the walls to provide cooling air, with additional openings in the wall nearest the air filter to supply cool air for combustion. In addition, provide ventilation openings along the top of the walls to release accumulated hot air. All ventilation openings should be fitted with mesh grilles to keep out pests. Arrange the exhaust pipe above the cooling air outlet to discharge in the same direction. Keep the exhaust system as short as possible and with the minimum number of bends.

Fuel tanks should ideally be ‘bunded’. A bunded tank consists of a tank mounted inside an outer housing large enough to accommodate the total contents of the tank, should it develop a leak. This ensures that fuel spills are contained and cannot get into the drainage system or the ground water.

E001.2.2: Inviting tenders for a generator

Prepare a tender short list. Every company on the short list must have a satisfactory arrangement with a competent installation contractor in the country where the equipment is to be installed and should be able to provide a long-term maintenance service or training for local technicians.

Tender invitations must include the following information:

1. Client: Name of the client.

2. Location: Site location.

3. Delivery/installation date: Specify the required date for delivery/installation should be specified.

4. Payment arrangements: Specify currency, payment stages and other relevant information should be specified.

5. Information to be supplied by tenderers:

  • ​price (Incoterms)
  • full technical details of the proposed equipment including fuel consumption on full load: fuel consumption will be a significant factor in choosing a generator set if anticipated run-times are long and less significant if the generator will be used infrequently
  • details of the manufacturer’s in-country installation and service network
  • manufacturer’s infrastructure requirements (e.g. cable connections)
  • manufacturer’s detailed recommendations for the generator house layout, construction and ventilation.​​

6. The supply required: Either: single-phase, 2-wire (phase and neutral), and system voltage, for example 110V, 220V or 240V. Or: three-phase, 4-wire (three-phase and neutral) and system voltage, e.g. 380/220V or 415/240V. 

7. Supply frequency: 50 Hz or 60 Hz.

8. Connected equipment: A schedule listing every item of connected equipment, including cold rooms, freezer rooms, refrigerators and freezers. In addition, list all other equipment for which standby power is required, such as computers, printers and electric lighting. For each item on the list, give the power requirement in kW. In the case of motors (e.g. cold room compressors) give the method of starting, e.g. direct-on-line (DOL). If you cannot find this information, give full details of each item of equipment, including manufacturer and model number, and request the tenderer to obtain the missing data.

9. Site conditions: Ambient temperature, humidity and altitude affect generator performance. Give the annual maximum and minimum temperature at the site in degrees centigrade, the maximum and minimum relative humidity in percent and the altitude of the site above sea level in meters.

10. Mounting method: Skid mounted. (Mobile units are available, but are not appropriate for a fixed installation.)

11. Weather protection: State whether the generator should be supplied as an open or weather-protected set. Open sets will be housed in a generator house. Weather-protected sets may be mounted outdoors.

12. Soundproofing: Sound-proofed housings are usually expensive. A locally-made masonry enclosure is often cheaper and, in the case of units installed outside, they also provide protection against the weather (see above figure).

13. Fuel: Diesel is universal for all but the smallest portable generators. Natural gas might be required in areas with stringent air pollution regulations.

14. Engine start: If automatic mains-failure start and/or shut down are needed, this must be clearly stated. Otherwise specify hand and/or electric start, complete with battery (even with electric start, it is useful to have a hand-start facility when the battery is flat or missing).

15. Engine monitoring facilities: Over-heating, low oil pressure, battery charging ammeter or indicator. Automatic engine shut-down in the event of over-heating, low oil pressure or broken fan belt. Engine monitoring meters and indicators may be mounted on the control panel.

16. Control panel: Integrated (set-mounted) or free-standing control panel. Integrated control panels must be mounted on anti-vibration mountings. Instrumentation should include:

  • one ammeter per phase 
  • one voltmeter and selector switch (to monitor each phase-phase and phase-neutral voltage)
  • a frequency meter
  • an hours-run meter.

17. Fuel tank capacity: Sufficient to allow a minimum of 72 hours continuous running and should be bundled.

18. Exhaust pipework: Run length and bends needed to ensure discharge in a safe location.

19. Spare parts: Either: the supplier must have an effective service network in-country. Or: an adequate supply of spare parts and consumables, sufficient for a minimum of two years of normal operation, as recommended by the set manufacturer, should be ordered.

20. Installation: It should be specified whether the equipment is to be installed and commissioned by the manufacturer’s in-country agent (strongly recommended), or by another party.

21. Training: The manufacturer, or installer, must train vaccine store staff and maintenance technicians in the use of the equipment and must provide comprehensive operating and service manuals in the appropriate language.

22. Maintenance agreement: Wherever possible, the equipment should be maintained by the set manufacturer’s in-country service agent. The tender documents should clearly specify the length of the maintenance agreement, the minimum requirements for routine maintenance and the maximum acceptable response time in the event of an emergency; e.g. equipment failure during a power outage.

E001.2.3: Choosing a supplier

The lowest bidder is not always the cheapest when lifetime operating costs are considered. Significant factors which reduce operating costs include:

  • Local availability of technical expertise and spare parts: Tenderers without a local service network should generally be excluded from consideration.
  • Fuel consumption: A model with low fuel consumption may be cheaper to operate over its whole working life than a model with higher fuel consumption but a lower purchase price.
  • Revolutions per minute (RPM): Slow running generators with ratings below 1800 RPM have longer working lives. Models running at 3000 to 3600 RPM generally require more maintenance, have greater fuel consumption and a higher rate of mechanical wear. A cheap high RPM model may be a poorer choice than a more expensive low RPM model.

E001.2.4: Suppliers of standby generators

A list of standby generator suppliers can be found in the UNICEF Supply Catalogue. This list does not constitute an endorsement or imply any recommendation by WHO of any of the products contained therein. 

Fluctuations in the electricity supply can cause the premature failure of motors, compressors and other electrical and electronic components. Fortunately, fluctuations can be controlled effectively and damage can be avoided by installing a voltage stabilizer on the power line which supplies the equipment. In addition, a surge protection device is recommended to prevent damage in the event of lightning induced spikes on the supply line. Lightning protection should also be included in areas where lightning is common.

Wherever voltage fluctuations exceed ±7%of the rated voltage at the supply point, WHO recommends that refrigeration equipment should be connected to the mains supply via a voltage stabilizer. This applies to cold rooms, freezer rooms, vaccine refrigerators and vaccine and icepack freezers at any level in the cold chain.

Associated electronic temperature monitoring equipment and computers should also be connected to a voltage-regulated circuit; this type of equipment is particularly sensitive to voltage fluctuations and to lightning-induced power surges.

There are various types of surge protectors. Some can survive only a limited number of surge events and with this type of equipment it is essential to stock an adequate stock of replacement components and to know how to replace them in the event of a failure.

It is generally good practice to ensure that refrigeration equipment and temperature monitoring/computers are supplied by separate dedicated supplies with separate voltage stabilizers. This ensures that the load variation of the refrigeration equipment does not adversely affect the electronic equipment, and enables the most appropriate type of voltage stabilizer to be chosen for each of the two load types.

Finally, the cost and design life of available equipment vary widely, with a design life of up to 50 years possible for highly critical applications. Large vaccine stores can hold hundreds of thousands of dollars' worth of vaccine; the cost of losing this inventory must be considered when choosing a voltage stabilizer and/or surge protector. It may be economically justifiable to install a more expensive system if it is more reliable and longer lasting.

E001.3.1: Types of stabilizer

The chosen voltage stabilizer must be able to cope with the full range of voltage fluctuations found at the vaccine store site. 

Servo-mechanical voltage stabilizers: These provide a reliable and economical method of stabilizing mains voltage range variations of up to 50%. They use a proven technology that combines electro-mechanical components with electronic sensing and control to give a continuous, smooth and very stable output voltage. Servo-mechanical voltage stabilizers have some moving parts which, depending on the application, will require a small amount of low-level maintenance after a long period of time. This technology is the most suitable one for primary vaccine stores and for larger sub-national stores. A disadvantage of the technology is its slow response time to voltage changes, but this is not considered to be a major drawback for cold store equipment. Another disadvantage is that it may be less reliable than tap-changing, particularly if the equipment is not properly maintained.

Electronic voltage stabilizers: A solid-state continuous-acting electronic voltage stabilizer provides a better alternative for applications requiring extremely fast correction speed, or applications located in hostile climatic conditions. A problem with cheaper models of this type of equipment is that they often incorporate a cooling fan. These may clog up in dusty conditions. Alternatives which rely entirely on convection cooling are available, but they are typically more expensive than servo-mechanical devices. 

Tap-changing voltage stabilizers and conditioners: A number of different tap-changing regulators are available; some are more reliable than others. A common type, used by many manufacturers, incorporates electronic tap-changing techniques. This type is prone to failure due to switching stresses. The more reliable devices use relays. For less sensitive equipment, where the output voltage only needs to be maintained within broad limits, a tap-changing solution is acceptable. All tap-changing regulators produce voltage jumps at the moment of tap-changing. Fortunately, refrigeration and air-conditioning units can accept these jumps. Tap-changing regulators may be unsuitable for loads such as sensitive monitoring equipment because they can cause graphic distortion or data loss. If ignored, this will eventually shorten the life of the connected equipment or cause expensive damage. Tap-changing regulators are an appropriate choice for stabilizing the supply to individual refrigerators or freezers in small sub-national stores and at service point level. As an example, one widely used unit can control output voltages between -8% to +9% when the input voltage varies between -34% to +26%. These units should always include a time delay cut out to protect against high/low voltage damage to refrigeration compressors. High capacity tap-changing units are available for cold rooms but are typically more expensive than equivalent servo-mechanical units.

E001.3.2: When to install a voltage stabilizer

Voltage stabilizers are strongly recommended whenever new vaccine refrigeration equipment is being installed, particularly if electricity supply to the site is problematic. If existing vaccine cold room motors, compressors, relays and other related electric equipment suffer frequent failure, this is a good indication that the stability of the mains supply is poor.

If the area surrounding the vaccine store is under development, there is a risk that the development of the electricity supply will not match growing demand. This can lead to an unstable, unreliable or fluctuating electricity supply. In such situations it is prudent to install voltage regulation equipment as a precautionary measure.

E001.3.3: Inviting tenders for a voltage stabilizer

Prepare a tender short list and provide bidders with the following information:

  1. Rated mains supply: Either: Single phase, two-wire (phase and neutral) and system voltage, for example 110V, 220V or 240V. Or: Three-phase, four-wire (three-phase and neutral) and system voltage, for example: 380/220V or 415/240V.
  2. Supply frequency: 50 Hz or 60 Hz.
  3. Measured voltage and frequency fluctuations: A qualified electrical engineer should be asked to obtain these measurements, which should be taken at frequent intervals over a period of at least one week. Allow for all potential loads and allow also for seasonal load variations.
  4. Electrical storm activity: Indicate the frequency and intensity of electrical storms.
  5. Connected equipment: Provide a schedule listing every item of connected equipment, including cold rooms, freezer rooms, refrigerators and freezers. In addition, list all other equipment for which voltage regulation and surge protection is required, such as computers, printers and electric lighting. For each item on the list, give the power requirement in kW. In the case of motors (e.g. cold room compressors), give the method of starting, e.g. direct-on-line (DOL). If you cannot find this information, give full details of each item of equipment, including manufacturer and model number and request the tenderer to obtain the missing data.


     
  6. Site conditions: Peak ambient temperature and humidity may affect equipment performance. Give the annual maximum temperature at the site in degrees centigrade together with the maximum relative humidity in percent.
  7. Generator: If there is a standby generator, full details of the unit, including make, model, kVA rating, start method (manual or automatic mains- failure) and stop method (manual or mains-resumption), should be provided.

E001.3.4: Suppliers of voltage stabilizers

A list of prequalified voltage stabilizers can be found in Section E007 of the Catalogue. A list of voltage stabilizer suppliers can also be found in the UNICEF Supply Catalogue. These lists do not constitute an endorsement or imply any recommendation by the World Health Organization of any of the products contained therein.

Solar power systems can be considered for walk-in cold rooms and freezer rooms (CR-FR) where no electrical power is supplied, in situations where sustaining a reliable electrical supply is not possible, where power costs are not affordable, or where fuel and technical support is difficult and costly to obtain.

Energy requirements for CR-FR are significantly higher than solar-powered vaccine refrigerators/freezers; while solar refrigerators operate on low voltage direct current (45 Vdc or lower) a CR-FR will require more dangerous — even lethal — voltages including high-voltage (Vdc) solar generation as well as high-voltage alternating current (usually greater than 120 Vac) supplied as either single or three phase supply. A solar-powered CR-FR will require both an inverter (i.e. converts Vdc to Vac) and a backup generator (Vac), which are components not included in PQS solar refrigerator/freezer kits.

Both the solar electricity system and the back-up generator must be capable of powering 100% of the CR-FR electrical requirements, including battery chargers powered by the back-up generator. For more details see equipment performance specification E001/PVAC: Solar power system for cold and freezer rooms.

The configuration of a PQS compliant solar power system for CR-FR is more complicated compared to a PQS solar refrigerator/freezer kit. It is significantly larger in size and requires a higher initial investment. Furthermore, members of the immunization community have less experience with these larger hybrid solar-backup generator systems compared to solar powered vaccine refrigeration. A limited collective experience with larger solar power systems coupled with a 100% back-up power generation requirement necessitates the careful consideration of the energy efficiency of the selected CR-FR, meticulous design, safe installation and long-term commitment to sustainability. 

Key requirements for the use of solar powered CR-FR include:

  • energy-efficient, site-specific design, to ensure adequate performance,
  • a qualified, professional electrician to ensure safe installation,

  • solar and generator servicing availability to sustain operation, and
  • planning and budgeting for repairs and eventual battery replacement.

Investing in an energy efficient CR-FR can reduce both the initial cost and long-term operating costs of the hybrid solar power system, in particular, by eliminating costly regular battery replacements. Like the site-specific design of the CR-FR, a site-specific power system design is needed to consider local ambient temperatures, solar radiation and battery autonomy, as well as the site's peak electrical requirements. PQS requires CR-FR designers to comply with international norms and standards for sizing power system equipment (e.g. Institute of Electrical and Electronics Engineers IEEE 1562: Guide for array and battery sizing in stand-alone photovoltaic (PV) systems).

Solar power and back-up generators, like any other electrical supply and distribution systems, will require the timely availability of qualified service providers to sustain, maintain and repair the system. It is essential to establish an ongoing service programme with qualified service providers to sustain system operation, and minimize the risks associated with the potentially lethal voltages and components of solar powered CR-FR that may not be known to local service workers.

Planning and budgeting for ongoing services, unexpected repairs and eventual component replacements will ensure that the CR-FR has power when needed. Like early solar-plus-battery vaccine refrigerator/freezers, the much larger and more costly CR-FR battery will eventually fail and need to be replaced. Only those who prepare and budget for battery replacement and other sustainability needs will be able to ensure that power continues to be available as needed.