Why PIPES: the principles behind the design
The primary motivation for developing an affordable and easy-to-produce-in-bulk alternative to PPEs was the extreme demand and scarcity of the standard PPEs. Towards developing alternative protection kits, we additionally considered few design constraints that are relevant in the present context:
The kit should provide a high degree of protection from virus exposure.
It should use inexpensive and locally available raw materials that can be manufactured in bulk. During an extended lockdown, it might not be possible to rely on materials that require shipment from elsewhere.
The process of manufacturing should not involve specialized machinery, and should require few and simple processing steps so that large batches can be produced in small/medium scale factories in many cities.
Although some compromise on comfort and looks can be accepted, it should nonetheless be usable for several hours.
The first two constraints can be met with one of the most readily available materials that is widely used in packaging industries: Polyethylene (PE). The non-breathable property of PE can be slightly less comfortable as a bodysuit when used for long hours, compared to the standard nonwoven polypropylene. However, PE provides complete protection from floating aerosols of sizes down to single-virus particles (120 nm). It is produced locally in almost every major or minor city. PE is usually extruded in the form of rolls of various sized flattened cylinders/tubes or “pipes”. Such extruded rolls thereby became our basic raw material of choice.
The major challenge was to achieve a high rate of production while ensuring protection and usability. Any kind of stitching and/or joining operations (e.g. ultrasonic welding) are time consuming and slow down the production.
The primary design consideration was to restrict to two simple operations: die-cut and hotwire-seal that are easily done in all packaging industries across the country. Dice can be made out of a ply board and pieces of blades from cutter knives for very low cost. Some ingenious maneuvers were required with various sizes of tubes to achieve this minimum number of operations, e.g., rubber bands and plastic laces for securing, breaking the entire suit into several parts. The most challenging part of the kit was the head cover, where breathability becomes important: this was addressed by the use of a nose piece tightly coupled to a full head cover, enabling a passage for breathing while protecting the rest of the face.
Viral contamination of COVID-19 happens through fine aerosols suspended in air. These are transported to the surface of the body in two ways: (i) passive transport due to ambient air flow and diffusion; (ii) active transport where the aerosols are drawn towards us by the action of inhalation during breathing which can be as high as 80 lpm. This active transport due to suction of aerosols to the body is separated from the passive transport on the rest of the bodysuit through the use of a nose piece that directs the airflow to a face mask. In the absence of any suction, the rest of the bodysuit has to provide protection only from the drifting aerosols and from direct contact with contaminated surfaces. Both are adequately provided by the PE materials. Large overlaps are provided wherever two pieces meet which provides adequate protection in the absence of any suction.
Is PIPES A PPE KIT?
PIPES is not a standard PPE kit. If you are wondering whether PIPES is suitable for you, please check “Who can use PIPES?” on this page.
PIPES meets many of the government specifications for PPEs while missing some. PIPES Kit samples made by some of our manufacturers have passed the synthetic blood penetration test with the ISO 16603 standard specified by the government. A comparison of PIPES with the current Government of India specifications for PPEs is shown in the linked table.
Who can use PIPES?
There are varying levels of exposure for people working with essential services to COVID-19 carriers and patients. Below we suggest a categorization of such service personnel, largely based on the Ministry of Health and Family Welfare (MoHFW) guidelines. From the feedback of various doctors and service personnel, we believe PIPES Full to be usable for level 1 and PIPES Comfort to be usable for levels 2 to 4.
Level 1: High Risk individuals (e.g., doctors in the ICU/critical care).
Level 2: Moderate or Medium Risk individuals (e.g.,. hospital sanitation staff, mortuary staff, staff handling laundary for patients).
Level 3: Low Risk individuals (e.g. ambulance drivers, ASHAs/Aanganwadi field staff, monitoring staff at quarantine facility, support staff, caretakers of patients)
Level 4: Security, administrative staff, police, courier, vendors, and other similar services who spend a lot of time outdoors and interact with unknown individuals.
Has any testing been done on PIPES?
Formal testing has been on samples submitted by our manufacturers, and they have passed the synthetic blood penetration test with the ISO 16603 standard (Muskan Packagers has received it from government lab).
Informally, we have sent the kits to many practicing doctors and received feedback, which was taken into consideration to refine the design.
For testing wearability, our team at IIT Kanpur wore the kit for several hours and measured the temperature under different parts of the kit. We observed that the temperature inside the kit was only slightly higher (within 2 degree Celcius) relative to the ambient temperature.
Is the material used in PIPES a health hazard?
Polyethylene does not pose any health hazard under normal environmental conditions. However, it is inflammable like many other synthetic fabrics, so care must be taken to keep away from fire.
Can PIPES be decontaminated and reused?
Although PIPES was designed for one-time use, it is possible to decontaminate and reuse it. If you plan to do so, the removal (doffing) after a day's use must be done carefully to avoid tearing of the materials and avoiding contact with the outer contaminated surface.
To decontaminate the kit with a WHO-recommended protocol, use household bleach liquid (main ingredient is sodium hypochlorite, typically available at 4% or 5% concentration; e.g. Rin ALA or Clorox) and dilute it in the ratio of 1:80 in water in a plastic bucket (metal container should not used). For example, mix 50 mL bleach solution in 4 litres of water in a small bucket for a single kit, or 500 mL of liquid in 40 liters of water in a plastic drum for multiple kits. Then immerse the kit in this diluted solution for 30 minutes. After 30 minutes, the kit can be taken out, rinsed with plain water, and dried.
If you are using a different solution of sodium hypochlorite or another source of free chlorine (e.g., bleaching powder), the dilution can be done to achieve a final concentration of 500 ppm or more of free chlorine. You can dissolve 100 gram of fresh bleaching powder for every 40 litre of water. Please store the bleaching powder in an airtight plastic bag in a cool and dry place (room temperature is OK, keep it away from direct sunlight and moisture). Do not use hot water for chlorine disinfection.
Other decontamination setups (such as EtO or EtOH/IPA), except high-temperature autoclave, can also be used.
How should PIPES be discarded? Can IT BE RECYCLED?
Collect all soiled kits in a large container for several days (coronavirus survives up to three days on plastic). They can then be sent for recycling of polyethylene. They should not be mixed with other solid waste.
We have recommended that PIPES manufacturers use recyclable polyethylene for making the kits.
Is PIPES Kit bio-degradable?
Polyethylene is not bio-degradable. This limitation also applies to nonwoven polypropylene used in standard PPE kits. However, as answered above, the polyethylene used in PIPES can be recycled.
How do I safely wear and remove PIPES kits?
If I don't have an N95 or even surgical mask, can I still use PIPES?
We expect that the mask will be procured by the users separately. However, if you are unable to find a proper mask, then as a backup option you can take 3 or 4 layers of fabric and put it under the nose piece (in PIPES Full model), which will keep the fabric in place after tightening by the straps. One reasonable option for fabric is to take layers of cotton/polyester sandwiched between nonwoven polypropylene (commonly used for making grocery bags or other carry bags in India), but if that is not feasible, any combination of available fabrics can be used (preferably the innermost layer should not be cotton).
What kind of factories can MAKE PIPES?
Plastic extrusion factories are best suited to manufacture the rolls of polyethylene cylinders/tubes/pipes of appropriate thickness and size, from which different components of the PIPES kit are made. Thicker transparent plastic sheets also need to be made or procured for the nose piece or the face shield.
However, if other local MSMEs can procure rolls of extruded plastic in bulk, they can easily set up the few simple steps for cutting/dicing and sealing/joining operations without much investment. Such factories may include sectors like textile, packaging or any other with some floor space and a labor force for serial production. The technical drawings are provided in the productions page to easily start the manufacturing.
Government of India, through the SAFE scheme of SIDBI, is providing quick (within 48 hours) loans at 5% interest rate, with no collateral property required, for manufacturing protective items for COVID-19.
Is there a centralized distributor for PIPES?
No. We encourage all local MSMEs in respective cities to start manufacturing and selling on their own, so that a possible exponential increase in demand for personal protection can be met in near future with local distribution. The current and potential manufacturers are listed here.