TechNet-21 - Forum

This forum provides a place for members to ask questions, share experiences, coordinate activities, and discuss recent developments in immunization.

Discussions tagged PQS

Power Quality Challenges in LMICs - Data and Analysis

Dear TechNet community, Poor power conditions are a major challenge to maintaining the vaccine cold chain in many LMICs, necessitating the development of specialized CCE such as ILRs and SDD refrigerators to help keep vaccines at safe temperatures in areas with limited or no mains power.  Even in places with an electrical grid connection or a generator, intermittent power can lead to ILRs running out of holdover, and erratic voltages can damage many types of medical devices and equipment. Despite these well-known issues, to date, data on power conditions in LMIC health facilities have been largely anecdotal or small-scale, which impedes evidence-based policymaking.  To quantify power availability and quality challenges, Global Good – in close partnership with Nigeria’s National Primary Health Care Development Agency (NPHCDA) and Kenya’s National Vaccines and Immunization Program (NVIP) – has compiled an analysis of mains power data reported over nearly 18 months by WHO-prequalified ILRs operating in health facilities across Nigeria and Kenya.  We are sharing this analysis in hopes of informing tangible improvements in both the performance and reliability of mains-powered CCE, as well as other priority medical devices and equipment utilized in health facilities within LMICs.

This analysis, co-authored by NPHCDA and NVIP officials, is based on approximately 96,000 facility-days of mains power data collected over a nearly 18-month period from ILRs operating in more than 300 health facilities spanning both countries.  These power data and other information collected by the ILRs belong to the respective countries; Global Good has been granted access to the data to enable collaboration with pertinent national and global stakeholders on tools to better utilize CCE data and make it actionable.  This overview of grid quality realities on the ground shows that multi-day interruptions are common, and that proper protection for medical equipment is essential given the widely varying line voltages experienced at most health facilities.   The initial analysis in this paper focuses on general power availability and quality at health facilities, with a few specific implications for CCE at those facilities including: 68% of the monitored devices in Kenya and 92% of those in Nigeria experienced power outages in excess of 48 hours. Therefore, long holdover times provide additional safety, even at those facilities with generally reliable mains power. Voltages fluctuate significantly, and stabilization can increase the ‘usable power’ availability at many health facilities – only 32% of the devices in Nigeria had access to in-range power (i.e., within 10% of nominal voltage) more than 30% of the time. However, with PQS-defined extended range voltage stabilization (i.e., 110 to 278 V), 58% of devices would have access to ‘usable power’ more than 30% of the time. Damaging high voltage events are common and can persist for hours or days – the graphs below show example voltage profiles from Kenya and Nigeria that would require protection between the socket and CCE (or other medical devices and equipment) to prevent damage to the electronic controls over time. These traces show data measured every 10 seconds, illustrating sustained voltages both above 400 V and below 100 V, and rapid fluctuations in and out of the CCE’s usable voltage range. Additional graphics and discussion are in the full document, and Global Good will continue analyzing data and sharing conclusions as more information is collected.  We hope this analysis will prove valuable for specifications- and standards-setting bodies, equipment designers and equipment purchasers, and we look forward to a vibrant discussion with the TechNet-21 community via this forum. We wish to acknowledge and extend our sincere appreciation to NPHCDA and NVIP for supporting and co-authoring this analysis.  We also want to acknowledge Qingdao Aucma Global Medical Co. for producing the WHO-prequalified ILRs that collected the study data, and eHealth Africa, Caroga Pharma Kenya Ltd, and Fenlab Ltd. for installation and service support in the two countries. The document is also availble here:    Best regards, Jenny Hu Senior Engineering Lead Global Good

Application Invitation: Energy Harvest Field Evaluation Support – Round Two

Supply Chain Strategic Focus Area Advance the Market Availability of Solar Energy Harvest Control-Equipped Cold Chain Equipment Date of notice: April 1, 2019   Summary: Manufacturers of World Health Organization (WHO) Performance, Quality and Safety (PQS) prequalified solar direct drive (SDD) appliances that can be coupled with a market-ready energy harvest control (EHC) option are invited to apply for new product field evaluation support. Selection of participants will be limited to funding available in 2019 with selection priority as follows: WHO PQS prequalified SDD and WHO PQS prequalified EHC; followed by: WHO PQS prequalified SDD and EHC with evidence of WHO PQS compliance; followed by: WHO PQS prequalified SDD and market-ready (i.e., post prototype) EHC. Application deadline: May 1, 2019, at 17:00 Pacific Daylight Time (Seattle time) Awards decision target date: May 15, 2019 SDD + EHC shipping date (by manufacturers): July–August 2019 Project completion target date: March 30, 2020 1.0 Goals and objectives The primary goal of Energy Harvest Field Evaluation Support (“the Project”) is to advance the availability and uptake of WHO PQS prequalified Energy Harvest Control (EHC) systems coupled to WHO PQS prequalified vaccine refrigerators, water-pack freezers, and combined vaccine refrigerator/ice pack freezers. It has now been demonstrated that solar direct drive (SDD) appliances coupled with an EHC can meet WHO prequalification requirements for safely harvesting excess SDD electrical energy and provide it for other health facility uses. There is interest in market development support to accelerate uptake of EHC systems. Energy harvesting is a new technology requiring technical support for immunization stakeholders to utilize appropriately. Also, as a new technology, WHO requires manufacturers to pass both a laboratory test and field evaluation for full prequalification. The field evaluation aspect is a newer WHO PQS requirement with significant cost to manufacturers and is an obstacle to market entry. To support the goal of advancing the availability and uptake of WHO PQS-prequalified EHC systems, Gavi has funded PATH to: (1) provide technical assistance to immunization stakeholders including Gavi, WHO, UNICEF, and national immunization decision makers on EHC-equipped SDDs and (2) provide support to competitively selected SDD manufacturers for fulfilling the WHO PQS field evaluation requirement. This Project will assess EHC and SDD technical performance, user acceptability, and system fit per WHO PQS field test requirements, including submitting a field evaluation to WHO PQS. PATH will be working with Sunny Day LLC, owned by Steve McCarney, as part of the Project. 2.0 Project roles and responsibilities Manufacturers will be required to apply per this invitation, and provide two complete SDD + EHC system kits including solar power system and any energy consuming loads (e.g., lights) included in, or loads recommended for use with, their kit. The manufacturers must provide the kits free of charge and delivered duty free (Incoterm DDF) to the PATH country office in Senegal, where Round One has been successfully completed. The kits are to include the minimum WHO PQS warranty requirements and will become the property of the host country at the conclusion of the Project, including transfer of warranty provisions to host country. Performance monitoring plan and monitoring equipment will be designed, provided, and installed by the Project in consultation with manufacturers. Installation of the SDD system including solar array will be by the manufacturer’s service provider (preferably located in Senegal or the West African region) and their costs will be covered by the Project. The Project and Project consultants will supervise all installation activities. Performance data will not be made public; however, it will be reported to WHO PQS, Gavi, UNICEF Supply Division, the manufacturer, and the Ministry of Health and Social Affairs (MOHSA) of the host country, Senegal. The Project will: Coordinate with the Senegal MOHSA to arrange for necessary approvals, including of sites and in-country partners. Coordinate with PATH office in country to support field evaluation. Review, comment, and approve project plan and field evaluation criteria. Communicate with SDD EHC manufacturer(s). In consultation with manufacturers, select and provide necessary health facility structural and electrical upgrades, loads, and monitoring devices. Develop evaluation protocol and obtain necessary research ethics approvals, at PATH and in-country. Coordinate all field evaluation requirement aspects with WHO PQS. Provide pre-installation site assessments, installation, and post installation support to service provider. Monitor field evaluation progress and data collection. Analyze and report field evaluation data. Review, comment on, and approve final reports to WHO PQS. Protect all qualitative and quantitative performance data as confidential, except to the parties noted above (WHO PQS, Gavi, UNICEF Supply Division, and Senegal MOHSA). 3.0 Application requirements Note to repeat applicants from Round One: your applications were sufficiently complete; therefore, please highlight any new information since your Round One application. Several changes are being implemented in Round Two. Your application must include user manuals for both the SDD appliance and the EHC system. If your application is selected, the Project will hire your service provider to: (1) conduct pre-installation site assessments at two health facilities selected by the Project for your specific equipment offering; (2) complete installation at two sites; and (3) return for user training at two sites. Manufacturer to provide outline of user training curriculum at time of application. Service provider to complete manufacturer-supplied commissioning form and submit all forms to PATH.     3.1 One-page summary of all products offered, appliance PQS code, solar array details, load options required or recommended, and delivery time (PATH office, Dakar, Senegal).     3.2 Support materials including all installation, maintenance, and user manuals, all component specification sheets (e.g., solar module, solar array support structure, array cable, EHC, EHC battery, and loads if provided) and if the proposed EHC is not yet WHO PQS prequalified, submit test results as evidence of compliance with the PQS   specifications. The application must present SDD appliance user manual, energy harvest user manual, user training curriculum outline, and commissioning forms for both the SDD and for the energy harvest system.     3.3 Manufacturer must agree in writing to: All terms and conditions noted in this invitation; Provide to the Project (at no cost to the Project) two complete systems delivered duty paid to PATH office in Senegal; Facilitate the contracting of your service provider for aforementioned tasks; Accept PATH-supplied energy loads (e.g., small fans, lights, fetal heart monitor operating on AA rechargeable batteries, 50 Watt hour Lithium battery packs for user selected loads, etc.); Relegate reporting responsibility to the Project; and Keep confidential all performance data, quantitative or qualitative (not to be made public).     3.4   Firm price quotation for service provider tasks noted above. Project to contract the service support by the manufacturer.      3.5   Send applications to or before 17:00 (Pacific Daylight Time) on May 1, 2019. Questions also should be emailed before 17:00 (Pacific Daylight Time) on May 1, 2019, to Your questions will be answered confidentially by PATH and/or PATH consultant Steve McCarney (directly and confidentially to the requestor).

REPOST: Refrigerated vehicles in immunization programmes survey

Dear colleagues,

On behalf of the WHO Performance, Quality and Safety (PQS) Secretariat, we are delighted to invite your response to our survey on the use of refrigerated vehicles in immunization programmes.

Refrigerated vehicles are crucial in the delivery of life-saving vaccines. Programmes that depend on one or a small number of refrigerated vehicles may be seriously impeded if a vehicle breaks down or is unable to maintain the temperature range that is required for the safe storage of vaccines.

The purpose of this survey is to gather information on the performance of refrigerated vehicles that are at least three years old. This information will be used to help PQS develop standards for refrigerated vehicles that meet the needs of immunization programmes. The information you provide will be extremely valuable to WHO PQS and the WHO Expanded Programme on Immunization (EPI). The survey can be accessed by clicking on the following link: The survey will remain open until October 31, 2018.
Please complete this survey for each vehicle that has been in regular use for more than three years for the purpose of carrying vaccines or other temperature sensitive pharmaceuticals. Please provide any available photographs where prompted in specific survey questions, by uploading photos directly to this platform.

Should you require further information on the survey, please contact the PQS Secretariat at

The survey will take approximately 20 minutes to complete, depending on the extent of your free-text answers.

Kind regards,

WHO PQS Secretariat

When should Ministries of Health use refrigerated vehicles to deliver vaccines?

Dear Colleagues, You are invited to contribute to a new discussion on 'When should Ministries of Health use refrigerated vehicle to deliver vaccines?'. Discussion co-moderated by James Cheyne and John Lloyd: There are at least four good reasons for using refrigerated vehicles to replace the classic pickup trucks loaded with cold boxes: The number of vaccines used in national immunization programmes has roughly doubled over the past 20 years and the number of new vaccine introductions is likely to increasing at a similar rate over at the next ten years. Larger volumes of vaccines will need larger vehicles. Refrigerated vehicles with three or four times the carrying capacity cost about the same as a typical pickup truck including the cost of the cost boxes and ice packs. Refrigerated vehicles eliminate the need to freeze hundreds of ice packs for each trip. Furthermore, continuous temperature monitoring in refrigerated vehicles is likely to reduce the amount of vaccine frozen in transit Larger capacity vehicles are better adapted to make round trips to deliver vaccines to several remote stores, saving both fuel and time. There are also at least four reasons for retaining pickup vehicles that deliver the vaccine in cold boxes and not investing in refrigerated vehicles: Existing delivery routes can continue to be used without the need for new route planning and new training for drivers and heath staff. Refrigerated vehicles can be difficult to maintain and spare parts for both the vehicle and the refrigeration unit are not always easy to source. Even with good maintenance and repair services available a backup refrigerated vehicle is needed to keep the deliveries moving when the first vehicle is being serviced or repaired after an accident. When not needed for vaccine deliveries pickup vehicles can be used more economically for non-vaccine deliveries. The world is not this simple, though.  We would like your thoughts and opinions on when you think refrigerated vehicles can be more effective and also when pickup trucks with cold boxes on the back can be the better option.  Or, of course, we would like to hear of any other options you know about to delivering large volumes of vaccines simply and reliably. Finally, if you are already using refrigerated vehicles, please have a look at WHO’s survey of refrigerated vehicles.  The purpose of the survey is to gather information on the performance of refrigerated vehicles that are three years old or older: The information will be used to help PQS develop standards for refrigerated vehicle meet the needs and operating environments of immunization programmes. Your help will be extremely valuable to WHO PQS and the WHO Expanded Programme of Immunization (EPI). Best regards from John and James.  We are both looking forward very much to debating your thoughts, ideas and suggestions.  Many thanks.

Does your immunization programme use refrigerated vehicles to deliver vaccines?

Good morning, If your immunization programme uses a refrigerated vehicle WHO needs your insights and experience to help guide and improve the standards of these vehicles. Take this opportunity to share your expertise with the community and contribute to global improvements.  Please post your answers to TechNet-21 to three questions below: Excluding routine servicing, has the vehicle needed to be repaired over the past three years? Inside the refrigerated body have you needed to fit new shelving or change the method of securing the vaccine or pharmaceutical load?  Have there been any problems with the in-cab temperature monitoring of the vaccine storage compartment during the past three years? 'A Yes' or 'No' answer to each question will be very helpful but even more useful for WHO would a sentence or two describing in more detail the problem and the solution you have adopted. These three questions are taken from a more comprehensive survey posted on TechNet-21 at: If you choose to answer more answers in the survey, that would be best of all, of course! Best regards.  James Cheyne - contractor to WHO.

REPOST: Remote Temperature Monitoring Devices (RTMDs) User Survey

WHO PQS is conducting a survey to learn from users of Remote Temperature Monitoring Devices (RTMDs) and inform the future of vaccine cold chain monitoring. Have you ever… Received a text, email or notifications from an RTMD? Interacted with RTMD hardware in the field, including responding to alarms? Setup RTMD hardware and/or software? Interacted with an online RTMD web portal? Conducted repairs or service on RTMDs? If so, we want YOU to help inform the future of RTMDs! Interested? Please send an email to to receive the survey link!  Best wishes, Denise Habimana Vaccine Cold Chain Technologies Program Officer at PATH

Participez à l'enquête sur l'utilisation programmatique des Dispositifs de Contrôle de Température à Distance (DCTD)

Le Secrétariat de l’OMS, par le biais de ses services chargés des normes de Performance, Qualité et Sécurité (PQS), mène une enquête pour recueillir des informations sur les systèmes DCTD pour mieux comprendre les besoins programmatiques des utilisateurs, gestionnaires et administrateurs de systèmes. Ces informations aideront à éclairer la mise au point des futurs produits et normes par le biais des profils de produits cibles (PPC) liés aux normes PQS. Les normes PQS de l’OMS utilisent les PPC pour informer le marché sur les caractéristiques et les aspirations futures concernant les produits, tout en orientant les politiques de développement de produits, les normes et les innovations connexes. Le public visé par cette enquête est le personnel ayant une expérience des programmes, dans le cadre de l’achat, de l’installation, de l’utilisation, de la gestion ou de l’entretien des systèmes DCTD. Seriez-vous intéressé de participer à notre enquête ? Veuillez envoyer un email à pour recevoir le lien! Meilleures salutations, Denise

Take the PQS survey on the use of refrigerated vehicles in immunization programmes

Dear colleagues,

On behalf of the WHO Performance, Quality and Safety (PQS) Secretariat, we are delighted to invite your response to our survey on the use of refrigerated vehicles in immunization programmes.

Refrigerated vehicles are crucial in the delivery of life-saving vaccines. Programmes that depend on one or a small number of refrigerated vehicles may be seriously impeded if a vehicle breaks down or is unable to maintain the temperature range that is required for the safe storage of vaccines.

The purpose of this survey is to gather information on the performance of refrigerated vehicles that are at least three years old. This information will be used to help PQS develop standards for refrigerated vehicles that meet the needs of immunization programmes. The information you provide will be extremely valuable to WHO PQS and the WHO Expanded Programme on Immunization (EPI). The survey can be accessed by clicking on the following link: The survey will remain open until October 31, 2018.
Please complete this survey for each vehicle that has been in regular use for more than three years for the purpose of carrying vaccines or other temperature sensitive pharmaceuticals. Please provide any available photographs where prompted in specific survey questions, by uploading photos directly to this platform.

Should you require further information on the survey, please contact the PQS Secretariat at

The survey will take approximately 20 minutes to complete, depending on the extent of your free-text answers.

Kind regards,

WHO PQS Secretariat

WHO PQS Manufacturer Consultation Report

Dear TechNet Community, On Tuesday 10th July 2018, the WHO Performance, Quality and Safety (PQS) Working Group conducted its first face-to-face technical consultation with manufacturers of PQS prequalified immunization products and devices from the E003 (Refrigerators and freezers) and E006 (Temperature Monitoring Devices) equipment categories - some of you may also have followed the event in real time via the TechNet-21 Twitter account. Thirty industry representatives took part in the meeting, alongside ten non-industry members and partners of the WHO PQS Working Group, to discuss and agree on a path forward for some significant proposed changes to immunization cold chain equipment standards. The PQS Manufacturer Consultation proved to be a highly successful first step towards greater collaboration with manufacturers on PQS standards-review and standards-setting processes. In particular it provided manufacturers with greater visibility on in-country realities and complexities and helped solicit industry insights and inputs on technical and product solutions to meet varying challenges in EPI program environments. More insights on the themes covered during the meeting as well as key discussion points and meeting outcomes have been provided in the PQS Manufacturer Consultation Report. The report can be accessed in the TechNet Library by clicking on the following link:  Enjoy the read! On behalf of the PQS Team,  Denise 

Live-Tweeting from the PQS Manufacturer Consultation is happening now on our TechNet-21 Twitter account!

... and all you have to do is follow the TechNet-21 Twitter account (or copy paste: in your internet browser) So far Denise's tweets have gained 779 impressions (tweets seen), that's awesome, and it's only the beginning. Don't miss out on pictures and discussion's insights!      

Live-Tweeting from the PQS Manufacturer Consultation on Tuesday, July 10th!

Dear TechNet-21 Colleagues, WHO PQS will be engaging with a selected group of PQS product manufacturers on Tuesday, July 10th to discuss and agree on a path forward for some significant proposed changes to immunization cold chain equipment standards. Although this is a closed event, the PQS Team and TechNet-21 are partnering to bring you exclusive insights from the meeting and I will be guest tweeting from the TechNet-21 Twitter account, sharing highlights and pictures from this first-of-its-kind event. All you have to do is follow the TechNet-21 Twitter account and check it on Tuesday, July 10th. If you don’t already follow TechNet-21 on Twitter (@TechNet21Mod) this is a great opportunity to start doing so! Looking forward to your virtual participation! Best wishes, Denise, on behalf of the PQS Team

Powering Auxiliary Loads in SDD Systems – Energy Harvesting: Is It the Best Alternative?

One of the beneficial features of SDD refrigerators is its relative simplicity. Electrically two wires from the solar array are directly connected to the compressor. This simplicity minimizes problems in the field and simplifies repairs. Energy harvesting technology introduces a great deal of electronic complexity and the complexity increases as a larger percent of the available energy is harvested. In the US the primary mode of failure of new refrigerators is the electronic circuitry. In the field there will be different types of energy harvesting devices coupled to different brands of refrigerators and the loads connected to the device will be of varying types, ie batteries, resistive loads, pumps etc. these factors will complicate the determination of  a cause of failure and will also complicate training of the repair person. If the energy harvesting device does fail there may not be the power necessary to call a repair person. If a USB charging port is created it is desirable to provide power throughout daylight hours so devices such as smart phones and I pads can get fully charged. The simpler harvesting technologies only provide auxiliary power when the refrigerator is not running and the more complex technologies could provide a USB port throughout the day if there is sufficient excess power when the refrigerator is running.    A simpler strategy to supply energy for auxiliary loads may be to add a small stand alone power system. A 100 watt $100 solar module could typically provide 500 watt hrs of continuously available reliable power. A USB charging station can be powered by a panel between 6 and 20 watts, the cost of the system would be between $15 and $50, and these systems do not require a battery. Although the idea of energy harvesting is intriguing it may not be the most reliable and cost effective way to supply power for auxiliary loads.

‘Freeze-free’ vaccine carriers – Where are they?

Three years after the freeze-free concept was reported at the September 2014 meeting of the WHO PQS Committee, the current expectation of availability remains ‘sometime next year’ and it appears that no product has passed the pre-qualification (E004/VC02-VP.1) testing yet. The current status of this product was presented at the last Technet Conference by WHO/PQS. During the resulting discussion, I noted five issues that seem to require attention: The outside dimensions and weight of the current prototype products are greater than the carriers used for forty years. We should see comparative data on dimensions, weight of the new and existing carriers because health workers will carry them, often for long distances. Evidence that the increased weight and bulk is operationally feasible should be confirmed by field testing. Freeze-protection in current carrier designs employs a built-in thermal buffer between icepacks and vaccines. The vaccine carrier including the thermal buffer begins the PQS test at +43C when the vaccine load is added at +5C. Evidence was not shared at the Technet meeting that in fact the new products can cool down the test load to below +10C within 8 hours and what is the maximum temperature during cool down? WHO mentioned, in the context of fixed thermostat refrigerators, that replacement of existing equipment by new models will proceed at a ‘natural’ replacement rate under GAVI CCEOP. If this method of replacement is also followed for vaccine carriers that often survive for 10 years, the renewal process will be too slow to avoid a considerable rate of freezing damage. One question raised at Technet has been raised without a satisfactory answer many times in the last 3 years: “Why is the freeze-free carrier the only solution pursued by global stakeholders”. For example, freezers that deliver their frozen icepacks at a few degrees below zero instead of -20C are feasible, but not explored. Phase change materials as a substitute for water/icepacks have been rejected by PQS without clear evidence. The current PQS focus on passive cooling vaccine carriers with icepacks is likely to be overtaken by active-cooled solutions based on adsorption or thermoelectric technology. This solution, in the form of Global Good’s ‘Indigo’ product, gives outreach teams 5 days or more autonomy and streamlines the process of daily short range activities by switching cooling on and off. In spite of these benefits the product has no specification nor pre-qualification test in PQS because it is an active cooler, not passive. The current process for establishing a new product is said to be more than two years. These questions among others reveal a weakness in the way that the global immunization community handles technology changes for immunization services. Innovation and optimization are treated as ‘solutions hunting for a problem’ instead of operational challenges to the development and growth of immunization – that call for new or improved technologies. Your opinions on how WHO/PQS might strengthen and accelerate this process will be, i I am sure, very welcome !

Temperature monitoring devices and Thermostat for vaccine refrigeration system

Dear Technet members, I would like to share my thoughts on the temperature monitoring devices and thermostal for vaccine refrigeration system. In the early days of EPI, temperature of the refrigerator was measured and displayed by a simple analogue thermometer which was either a bi-metal or stem type alcohol thermometer.  Twice daily the health worker records these temperature on the temperature monitoring sheet and posted on the door of the fridge.  Filled temperature records are collected, kept on the file at the end of each month and replaced by a new one.  Temperature recorded was the temperature obtained during that time when it was read.  There was no information on the temperatures during the night or between the time interval when temperatures were obtained.  These old thermometers need to be calibrated more often which was a big challenge at the remote health facility. To rectify the problem an electronic thermometer that could continuously record and display the temperature of the fridge was developed.  It does not need calibration till its lifetime of 2-3 years when it has to be replaced.  Average temperature readings could be read for the past 30 days.  The device was further developed to include a usb connector and with temperature alarm alert and temperature data could be downloaded for record and review purposes. The latest temperature monitoring and recording device has a temperature sensor placed inside the fridge and could send the temperature readings on a computer/cellphone and could further be accessed via cloud etc. All of the above temperature monitoring and recording devices are passive devices, in the sense that it does not take any corrective action if temperature excursions are encountered.  It is simply used to inform or alert the health worker that something is wrong with the fridge.  Corrective actions at health facility level relies on the health worker who is alone and frequently busy and not specifically trained to do the job of diagnosing the cause of the problem.  With shortage of the technical staff at the national/provincial/distric level, it is not expected to rectify the problem as early as it is needed thus causing potency problem to the vaccines, missed vaccine sessions and increase unopened vial vaccine wastage. Allow me to give information to each one who are not familiar with refrigeration system, that every vaccine refrigerator/freezer (with the exception of the absorption kerosene refrigerator) has a temperature control which is commonly called a “Thermostat”.  Thermostat is an active device (compared to a thermometer which is a passive device) which is connected in the electrical circuit component of the refrigerator.  Its main job is to regulate or control the temperature of the refrigerator according the temperature setting by the user.  The old thermostat control switch is numbered starting from 0 to say 5.  Each number has a corresponding cut-in and cut- out temperature. How does thermostat work? The purpose of all refrigeration system is to lower the temperature of the confined space below that of its immediate surrounding.  The confined space of the refrigerator is the vaccine storage compartment. The refrigerant compressor of the refrigeration system once connected to the grid or solar panel will continuously run to lower the temperature of the vaccine storage compartment thus putting the freeze-sensitive vaccines at risk.   Running compressor motor can be stopped by any of the following actions:  a) if power from the grid is manually disconnected by the user or accidental power shutdown; b) the overload protector of the compressor is automatically activated due to extreme heat and voltage fluctuation; and c) the thermostat which was set at a desired temperature is automatically activated. Please note that once the compressor is stopped by either of the above ways the temperature inside the vaccine storage compartment will continue to rise.  Operation of the refrigerator will commence again if either the refrigerator is manually connected to the grid, the overload protector cools down and voltage is back to the normal range or the thermostat automatically reach its cut-in set point.  Therefore, THERMOSTAT is an active device that automatically regulates the temperature between the cut-in temperature of +8°C and the cut-out temperature of +2°C of the vaccine storage compartment.  Cut-in temperature of +8°C is the temperature when refrigerator compressor motor will start and cut-out temperature of +2°C is the temperature when refrigerator compressor motor will stop to protect freeze sensitive vaccines from freezing. It is therefore very important call to action for the refrigeration system equipment manufacturer to further conduct a very thorough study to equip the vaccine refrigerator with a very accurate and precise thermostat control device that will work at various conditions in the field. WHO PQS has introduced new standards for refrigerators to have a sealed thermostat. This effort is highly appreciated hoping to reduce unopened vaccine vial wastage due to freezing temperature in the refrigerator.  If thermostat is not sealed untrained staff as in the previous refrigeration units will try to adjust the temperature setting of the thermostat thus placing the both freeze sensitive and not freeze sensitive vaccines at risk.  Electronic sealed thermostats are now used by equipment manufacturer.  Temperature settings of these thermostat can only be altered by a manufacturer trained technician. Recently, countries are receiving refrigeration equipment under the GAVI CCEOP project.  Equipment are laboratory tested and PQS compliant, however their performance could actually be tested at different and difficult environment and situations in the field.   To be able to assist the equipment manufacturer to develop a more accurate and precise thermostat, country’s EPI national program should monitor equipment performance and share feedback to TechNet for follow up actions. Hope this helps. Alejo H  Bejemino Consultant Medical Physics and Health Physics Services, Inc Philippines    

WHO Performance, Quality and Safety (PQS) Website Survey

Dear Technet21 Members, We are pleased to invite you to take part in our new survey about the WHO Performance, Quality and Safety (PQS) website. We want to make sure the website is functioning optimally for all its users, and so we are keen to learn more about why and how you use the PQS website, and what your personal experience has been. Answering the survey questions will take around 7-10 minutes of your time. The survey will remain open until the 30th of September and shortly after that we will share what we have learnt from you. The contact details you provide will be used only for this research, and any responses you provide that are reported publicly will be made anonymous. Please kindly access the survey on: PQS Webiste survey  ( If you choose not to complete the survey, but would still like to let us know your thoughts on the website, send us an email at Thank you for your participation and for supporting the PQS mission.

Isaac Gobina WHO 

When to consider solar, based on hours of mains/generator electricity available each day

I’ve been reading with great interest the most recent issue of Vaccine, which is dedicated to “Building Next-Generation Immunization Supply Chains”. I particularly enjoyed the following article but was surprised to read that the authors identified a discrepancy between WHO PQS and Gavi Cold Chain Equipment Optimization Platform guidance relating to solar refrigerators and under what conditions (how many hours of mains/generator electricity are available each day on average) they should be considered for vaccine storage. 'When are solar refrigerators less costly than on-grid refrigerators: A simulation modeling study' The article states: "To effectively maintain an adequate supply of life-saving vaccines in low and middle income countries, where electricity supplies can be capricious [1], the World Health Organization (WHO) currently recommends solar refrigerators for regions with less than four hours of electricity per day, on average, and electric mains-powered ice-lined refrigerators (ILRs) for areas with more reliable electricity [2]. Gavi recommends solar refrigerators for locations with fewer than eight hours of electricity per day or power outages that last more than 48 h [3].
[2] World Health Organization Department of Immunization, Vaccines and Biologicals Quality, Standards and Safety. PQS devices catalogue: prequalified
equipment for the Expanded Programme on Immunization (EPI); 2016 March 11.
[3] Gavi. Cold chain equipment optimisation platform technology guide; February 2016." I went back to the PQS Catalogue and the “Selecting a suitable energy source” graphic on page 35 (this also appears in the WHO-UNICEF solar guidance document). My understanding is that the guidance offered here is in fact the same as Gavi's, in other words solar - in addition to other solutions - should be considered at locations with fewer than eight hours of electricity per day (if the answer to the question "On average, how many hours a day is mains/generator electricity available?" is between 0 and 7). After some thought, I realised that the confusion has probably arisen from the way that solar is presented under the 0-3 box. Under 4-7 it is stated: “Use ice-lined refrigerator* rated 4 hours electricity a day, or consider solar”. However, it seems the “or consider solar” has (understandably) been missed by the authors of the journal article. I don't think this impacts the findings of the article in any way; however, it is worth calling out the discrepancy, as it’s clear that Platform and PQS guidance should be closely aligned if possible (and I think they are). It may be worthwhile to create a new, clearer version of the PQS graphic. I am in discussion with the PQS team in relation to this and hope to update members in future if a new graphic is developed. In summary, for a location with 0 to 7 hours of mains/generator electricity available each day, solar, long-term passive, or liquid petroleum gas solutions should all be considered. And for locations with 4 to 7hours of mains/generator electricity, ice-lined refrigerators rated 4 hours electricity a day should also be considered. Refer to the PQS Devices Catalogue for more information.

Cold Chain Equipment Optimization Platform - Technology Guide

Dear friends, Gavi, the Vaccine Alliance is very pleased to present the Cold Chain Equipment ‘Technology Guide’, to support the appropriate selection of modern, efficient and reliable technologies. Download the guide here.
Identifying the most appropriate equipment choices for each health facility is key to help ensure more facilities have adequate cold chain capacity, and that more facilities also have higher performing equipment that stays functional for longer periods of time. This in turn will help increase access to immunisation as well as greater vaccine safety and potency, and contribute to improvements in immunisation coverage and equity.
Developed by technical assistance providers, the Technology Guide offers comprehensive and regularly up-dated information on cold chain equipment and technologies and how to choose the solutions that meet the needs of each health facility. The Technology Guide covers the range of optimised on-grid and off-grid refrigerators and freezers. It also covers other new technologies such as new passive cooling devices and temperature monitoring solutions. The Guide provides clear advice and structured approach to CCE decision-making is intended in particular for use in health facilities and at lower levels of the cold chain.
The Technology Guide is also available as part of the TechNet ‘Cold Chain Equipment Management - Technical Resources’ page here.
The Technology Guide also explains which devices comply with the requirements of the recently launched Gavi Cold Chain Equipment Optimisation Platform. Platform eligible equipment and technologies include innovation that has been achieved via quality assurance provided by WHO Performance, Quality and Safety (PQS) specifications and additionally establishing target product profiles (TPPs) designed to ensure manufacturers also bring the next generation of equipment needed by countries. Click here for more information on the Platform, which is a new form of support to countries to improve access to appropriate and high-performing cold chain equipment.

La version française de l’outil de calcul du Coût Total de Possession (CTP) d’équipements de la chaîne du froid est maintenant disponible.

Outil de calcul du Coût Total de Possession d’équipements de la chaîne du froid
L’outil de calcul du Coût Total de Possession (CTP) d’équipements de la chaîne du froid a été développé afin d’assister les utilisateurs dans leur compréhension du coût d’achat et de maintenance des équipements de la chaîne du froid. L’outil peut être personnalisé pays par pays et calcule les dépenses en capital et en coûts d’opération pour les équipements préqualifié par le département Qualité et Sécurité de l’Organisation Mondiale de la Santé.
Pour accéder le CTP cliquez ici:

Reviews of the SunDanzer BFRV 55 solar direct-drive refrigerator

Choices, choices, choices – they are both the bane and blessing of our times. As immunization managers, we now have a wide array of PQS-prequalified cold chain equipment to choose from, but how do we make the right choices and get the best value for our bucks? The TechNet Product Reviews area helps you do just that, with users in the field, who are constantly ‘testing’ the product, giving you feedback about the equipment they are using be it refrigerators, thermometers or vaccine carriers. Take, for example, the SunDanzer BFRV 55 DC solar direct-drive refrigerator. Gopal Nadadur from Clinton Health Access Initiative (CHAI) writes, “As is widely acknowledged, improper installations are the cause of a significant percentage of malfunctioning or broken down refrigerators. Easier installation procedures could help to alleviate this problem.” And that is just what CHAI did, ensuring that the manufacturer was kept in the loop, allowing for improvements in product installation. Some of Gopal’s comments have to do with installation while the others recommend changes to the product itself or deal with maintenance. To list some of them: • Visual job aids to assist in routine maintenance and daily usage would be valuable. • The product’s fasteners use the English system of units, all countries where the SDD will be installed use metric sizes. Although the tools are provided with the unit, it would be simpler for all parts to be in metric units if replacement parts need to be procured in country. • Include spare parts of all components needed, especially simple parts that are likely to be easily misplaced (nuts, bolts, screws, etc.). • Could a modified mounting solution be developed for positioning the E-W array at the top convergence of both sides of the roof? This would add greater flexibility to mount on different roof orientations. Note: The manufacturer has accepted this feedback and is working on a solution to this problem. • Constructing the mounting frame of the solar arrays around a pole proved problematic, since some of the fasteners, brackets, nuts, bolts, and screws were confusing to position properly. Need a simpler design and better instructions. Refrigerator • Handles on the side of the refrigerator made carrying it and positioning it in the vaccine storage room easy. • The ON-OFF switch is located in a corner at the back of the fridge. It can be repositioned to be easier to locate. Hamadou Modibo Dicko in his review says that he would “fully recommend this equipment as it has been working well according to agents on the ground”. He lauds the manufacturer’s honesty in informing him that the equipment may not work efficiently at sites that receive heavy rainfall and where the skies are clouded for large parts of the year. However, the staff has had difficulties using all the available baskets at once, and he suggests that the manufacturer should make suitable modifications to this design feature. The third review is from Kshem Prasad, who evaluated the units that were installed in Kenya during 2012. He states that, “most of the models were found having a distorted ice-lining, which is factory installed with some gel compound into the unit. Most likely, it is suspected that the plastic deformation of the ice lining on the 4 walls, occurred during the storage and transport in the container, during which the units were exposed to temperatures higher than expected.” The deformation has compromised efficient cooling and interferes with proper placement of the baskets. The UNICEF SD has communicated these limitations to the manufacturer and the latter is expected to come up with a solution in its new models. You can read the detailed reviews of the product here: You can also comment on the reviews above or submit your own review:

Considering a Max/Min range for Vaccine Storage Capacity in refrigerators

The percent difference between the gross refrigerator (ILRs and SDDs) volumes quoted in the PQS Catalogue and the net vaccine storage volume varies from 29.6% to 88.6 %. This is a wide variation for front opening fridges, due to space for air-circulation. Increasingly, new models of ILR and SDD are emerging with cooled internal walls and cooled ceilings. Some of these models maintain a satisfactory internal temperature distribution whether they are packed according to the test procedure (with air spaces) or when the vaccine load fills the whole gross volume (without air spaces). The impact of this finding is that the storage capacity of a new model of ILR or SDD may be double or even treble the catalogue figure. The difference in capacity at intermediate levels of storage in-country will affect the economic decision to procure a cold room or maintain a bank of ILRs or SDDs. Running costs will be affected. Cold-chain equipment planners be made aware of this issue when they choose new equipment and when they re-equip stores. What about these next steps – just my own suggestion? we maintain the method of loading by the test laboratories that uses 1.0 and 0.5Lt. boxes and we maintain the 'net vaccine storage capacity' measured by the laboratory. But I suggest that this parameter be titled 'Minimum vaccine storage capacity'. we maintain the manufacturer's gross capacity, but we add a 'Maximum vaccine storage capacity' that is measured by the laboratory as the maximum vaccine load (represented by the dummy load) without airspaces, without baskets or shelves IF this extra loading step is done (Optional, requested by client) then: ◦ the Maximum vaccine storage capacity is reported by the lab. and entered in the catalogue ◦ the rest of the testing that requires a dummy load would be loaded according to the Maximum capacity IF it is not done, the Maximum capacity will be the same as the minimum and the Minimum capacity will be loaded for the rest of the testing. the country clients for cold chain equipment would be informed that the laboratory reports generate a range of capacity (Min./Max) for each refrigerator and that, within this range and according to the vaccines they use, the country managers can choose a value for the Vaccine storage capacity in that country. The consequence of this approach is that ILRs and SDDs with satisfactory temperature disitribution performance even when fully loaded, will be more efficiently loaded, less numerous in larger stores and less energy and space consuming. Usually, this would result in lower cost of procurent and maintenance. Also, the coldchain manager has an opportunity, even an obligation, to check the capacity that he/she will use when equipping stores to better correspond to the vaccines in use. Finally, if an equipment model requires airspaces to assure a correct temperature range, then the manufacturer does not invoke the additional measuremnt during testing - the dummy vaccine load simply reverts to the current procedure.

How to keep up to date with changes to the PQS Catalogue

Newly-prequalified cold chain equipment is regularly added to the PQS Catalogue. To keep up-to-date with changes to the PQS Catalogue, you can now follow the PQS updates feed on Twitter:

In addition to listing newly-prequalified equipment, the feed also highlights new and updated target product profiles (TPP), as well as PQS news and issues.

The PQS Catalogue provides a detailed list of all immunization-related products currently prequalified by WHO. Individual datasheets for each product can be found in the following categories:

E001 Cold rooms and freezer rooms
E003 Refrigerators and freezers
E004 Cold boxes and vaccine carriers
E005 Coolant-packs
E006 Temperature monitoring devices
E007 Cold chain accessories
E008 Injection devices (for immunization)
E010 Waste management equipment
E013 Injection devices (therapeutic)

The entire PQS Catalogue is also available as a PDF document on the PQS Catalogue website:

This document includes datasheets for every prequalified product, as well as guidance notes to help purchasers make informed choices.

The PQS Catalogue is regularly updated. To report defects affecting any product in the PQS Catalogue, please contact the PQS team (

Have your say on cold chain equipment

Next month, TechNet launches a new area for members to review cold chain equipment. The 'Reviews' area will list all PQS-prequalified devices and equipment, arranged into the following PQS categories: Cold rooms and freezer rooms (E001) Refrigerators and freezers (E003) Insulated containers and accessories (E004, E005) Temperature monitoring devices (E006) Injection devices for immunization (E008) Waste management equipment (E010) Therapeutic injection devices (E013) Members will be able to read and comment on the reviews of other members, and also submit their own. Reviews can be long or short, positive or negative, comprehensive in scope or simply anecdotal, and can be supported with photos, videos, PDFs, or other relevant material. The first category that will be launched is 'Refrigerators and freezers', with the others coming shortly after. We hope the new area will encourage lively debate and valuable information-sharing of field experiences. If you would like to know more about the new area, please contact the moderator.

PQS sheets: Solar refrigeration

The data given for solar-powered refrigerators in the PQS sheets is not given consistently enough so that comparisons of various models can be made. The data needed for a fair comparison most often is energy consumption at 32 deg C without ice making, energy use with ice making and quantity of ice made. It would also be useful to know the number of days of autonomy time for direct-drive refrigerators. Looking at the PQS sheets it is not always clear how to obtain total energy consumption when refrigerator and freezer consumption are given separately. Perhaps it should state whether or not it is a two compressor model and if the refrigerator and freezer consumption should be added together to obtain the total energy consumption. Another confusing point on the PQS sheets is that the solar radiation reference period is often given without energy consumption data or recommended solar array size. Without this information the radiation reference period has little meaning. There are few places in the world where average daily temperatures are over 32 deg C. It is important to know if afternoon temperatures peak at 43 deg C that the vaccines will be safely stored and remain between 2 deg C and 8 deg C. However, the average ambient temperature will probably be at 32 deg C or below and the stable running consumption at 32 deg C will be used for system sizing. The latest data I received for a direct drive refrigerator E003/037, for example, gives no energy consumption at any temperatures or any recommendations on a array sizing, it does however give the solar radiation reference period, which alone would be no help judging efficiency or in sizing a system. When the compressor for this model (E003/037) was switched to an AC model so that it could be transformed into an ice lined refrigerator (E003/036) for some reason stable run energy consumption at 43 deg C was given in addition the cool down energy consumption was listed. If the pertinent data is not consistently published there is no incentive for a manufacture to build a more efficient product and no way for a buyer to make an intelligent purchasing decision. I hope the PQS sheets can be transformed into a more useful document.

Change your internet browser favourite to access the PQS web page

Dear all, The PQS team is glad to announce that you now have access to the new PQS webpage generated by our database at: The new PQS home page gives you easy access to prequalified devices, vaccines and laboratories. It also contains various links related to vaccines and equipment that are not part of the database. The prequalified devices and equipment page allows you to download the latest version of the pdf catalogue. You can also provide us with feedback by filling in the feedback form. The PQS team is particularly interested in any feedback you might have regarding the site. More importantly we would like to encourage users (Agencies, consultants and country staff) to provide us with information on the good or bad performance of equipment and devices in the field. The feedback page also allows you to include photographs. As with the previous layout, products are organized by category. Each category page give you access to a downloadable pdf datasheet for the prequalified products in the chosen category. The category pages include two functions: a filtered product search, and access to category-specific documentation, including guidelines, performance specifications and verification protocols. The PQS team

PQS data and array sizing for direct drive refrigerator

PQS Data I was recently trying to compare PQS data for direct drive refrigerators. Data for two parameters of prime importance are not always given: - Solar radiation reference period - Power consumption: Stable Running Data is also usually given for 43 deg C and sometimes for 32 deg C. Data at 32 deg C is most useful because it is more typical of average daily temperatures in developing countries. I don’t think there is tropical location where 24-hour average temperatures are near 43 deg C. For the HBC-60 the power consumption at stable running was, 1820 watt hours/day for a 6 KWH/m^2/day and the stated array sizing required was 180 watts. A 180 watt array on a 6 KWH/m^2/day could at most generate 1080 watt hours/day. Am I interpreting the data correctly? Do prices in the PQS sheets include solar panels? This is not always clear. If a direct drive unit needs a battery it would be of value to know the size and type of battery. Array Sizing for Direct Drive Systems There are very few places in the world where the minimum average daily solar radiation is 6 KWH/m^2/day. For reliable system sizing it would be better to give the data for 3.5 KWH/m^2/day or the proposed 4.5 KWH/m^2/day. Unfortunately, average daily solar radiation data for direct drive systems does not give enough information for system sizing. It typically takes about 50 watts of solar power to start the compressors in a direct drive refrigerator. The number of hours a compressor operates cannot be calculated from accumulated KWH/m^2/day data. The same KWH/m^2/day can be obtained for uniformly cloudy conditions or partly sunny conditions, however with these two conditions the number of hours per day the compressors operates per day will probably be different. What is needed to properly size a direct drive system is hourly data, which is unfortunately not available for developing countries. Given this situation, more research is needed into how to size the array for direct drive systems.
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