Being in charge of setting up a laboratory is a daunting task, and involves tackling the demanding ordeal of sourcing the latest computers, the shiniest benches, the most advanced equipment, and a trusty autoclave. Autoclaves are an essential piece of equipment for the majority of biology laboratories, and choosing the incorrect one can be a costly decision. This process can be lengthy and confusing; autoclaves come in many shapes, sizes, capacities, and styles. So how exactly is a facilities manager supposed to make an informed decision while balancing all their other responsibilities? Easy; they can read this post which outlines autoclaves, their features, and how to choose one!
Determining your Sterilization needs; Autoclave Size.
When deciding on your sterilization needs, ask yourself and/or your users what types of objects will be sterilized. This could include glassware, tools, bioreactors, liquid media, fermentation devices, etc. It’s important to ensure that your largest items will be able to fit inside the autoclave chamber. Autoclave sizes are typically measured in liters, measuring the total volume of the inside of the chamber. Keep in mind, however, that effective chamber volume is usually lower than the described volume and should be a factor in your evaluation.
Another valid consideration is to measure the exact capacity per cycle of the autoclave to determine throughput. To determine this, simply consider the configuration of the autoclave you have in mind, the types, sizes, and quantities of the items being sterilized, and the effective volume. Be sure to double-check the number of items that will fit, as this a very important determinant of throughput. Once these three values are determined, you can understand the effective throughput; and then be able to decide on the size of the autoclave you need, should you require a different output.
It’s important to realize that the size and type of autoclave you choose can have a large effect on your lab’s efficiency. One must consider the frequency of loads, time per cycle, load size, and the number of users before making a decision. If your lab has a steady throughput requirement, you might benefit from having several medium-sized autoclaves, and by staggering use, you can ensure a high throughput. Having a large single autoclave might be appealing at first, but any malfunctions, breakdowns, or maintenance can cause a huge drop in efficiency.
Determining your Installation Utilities and Compatibility
Autoclaves can have varying voltage requirements, so your electricity source and input is an important consideration. Some autoclaves require up to 240V outlets, which aren’t as accessible as standard 120V outlets. Access to water and/or steam are also essential to an autoclave’s functionality. Traditional autoclaves require an external water main or steam main to work. Others, however, might not require a water intake and can simply function with water that is added into the chamber. If you have an autoclave in mind, be sure to check its installation requirements and compatibility with your water and electricity inputs.
In addition to ensuring compatibility, it’s crucial to determine installation needs. Outside of the cost of the actual unit, it can be costly in terms of the time and money it takes to install your autoclave. Should your autoclave require a steam intake, a water drainage solution, or a higher voltage to function, these can easily drive up your total costs. Aside from this, a large in-the-wall autoclave requires a fair amount of square footage to be functional at optimal output, making it a tough decision should your laboratory space be limited. Choosing the right autoclave that is compatible with your facility and is easy to install can save you a lot of time and space!
Determining your Total Costs Over Time
Finally, choosing an autoclave comes down to the total cost of ownership, not just the upfront costs of the unit itself. It’s important to mention that as a facilities manager, your costs don’t go away as soon as you’ve purchased your new autoclave. There are maintenance costs, breakdown costs, and replacement costs that will inevitably come up. Autoclaves are robust devices, but the combination of high usage and the elements, it shouldn’t come as a surprise that your autoclave will need some maintenance every now and then. Regular upkeep involves replacing parts, paying a technician, and managing costs during downtime.
Typically,autoclave gaskets are the most commonly replaced item. The cost of replacing gaskets can run up to a few thousand dollars during ownership if gaskets need to be replaced often. Gaskets typically require changing due to the intense heat and pressure that develops during a cycle, subjecting gaskets to harsh conditions. Of course, gasket design and material quality determine the frequency of required changes, but gaskets that are changed often will only serve to drive up your costs, even though the per-part cost might initially seem cheap. A well functioning gasket ensures autoclave longevity and has a lower likelihood of breaking. Choosing an autoclave that is easy to maintain, and has low costs over time can save you a lot of time and money!
When choosing an autoclave, keeping in mind your costs over time, your facility’s utilities, and the throughput requirements can help you make an informed decision. One of our products, the TOMY SX Series autoclaves provides a lot of great benefits while keeping costs down. It features a top-loading autoclave, that requires just water to get up and running. The gaskets themselves are typically replaced once every three years, keeping costs over time to a minimal. With a minimal installation investment, easy to use, and a robust build, the TOMY SX Series autoclaves should be able to meet all of your needs with ease.
Should you need any more information regarding TOMY autoclaves, or just have some questions regarding features, repair and maintenance of autoclaves, please feel free to reach out to us email@example.com. Alternatively, you can fill out this contact form as well, and we can get back to you shortly.
Autoclaves function primarily through either gravity or vacuum-induced or pre-vacuum (prevac) sterilization methods, though some types of autoclaves combine both methods to sterilize. Both types of autoclaves sterilize through high temperature steam and use pressure as a means to allow steam to displace ambient air in the chamber to penetrate sterilization media, the means by which these mechanisms occur differ and thus, are more conducive to certain types of media over others. This article will outline the basic function of these autoclaves and list the types of sterilization media most associated with each type of autoclave.
Gravity autoclaving, also known as gravity displacement autoclaving is the most basic form and is suitable for sterilizing the most common laboratory media, including steel utensils, glassware, and bio-hazardous waste. Gravity-induced autoclaving involves pumping steam into the autoclave chamber, which displaces the ambient air and forces it out of exhaust valves, so that the remaining steam can sterilize the contents. This mechanism is advantageous in the simplicity of its design and lack of dependency on peripheral mechanisms to displace ambient air with steam, making these types of autoclaves more affordable and dependable. The majority of autoclave media, or items to be sterilized are simple in design and do not contain spaces or obstacles for steam to penetrate within, thus the steam displacement function is ample for proper sterilization. It is for these reasons that gravity autoclaves are the most common types of autoclaves in the market and are usually the recommended type of autoclave for most uses.
On the other hand, vacuum autoclaving, also known as pre-vacuum autoclaving or sterilizing is more suited in cases where air cannot be easily removed from sterilization media. This may include large or porous items such as animal cages and bedding sterilization as well as wrapped surgical kits. The vacuum function in these autoclaves allows deeper sterilization of the contents, as it completely evacuates the ambient air within, allowing high-temperature steam to penetrate and sterilize areas that would normally be occupied by ambient air, and can be more efficient at sterilizing certain items with hard-to-reach areas within.
Autoclave Media and the Appropriate Autoclave Type
As mentioned above, your choice of an autoclave system largely depends on your autoclave media, ie. the items to be sterilized. Overall, steam sterilization is highly dependable, effective, fast, and non-toxic, and offers an inexpensive way to rapidly heat and penetrate the chamber’s contents, including appropriately contained liquids. However, this method cannot sterilize powders or oils, and can only work with heat and moisture-resistant goods. Keeping this in mind, below is a summary of the primary types of media used by gravity and vacuum-autoclave types.
Gravity autoclaves are appropriate for sterilizing non-porous items (i.e. those with a hard surface):
Most metals, particularly stainless steel surgical instruments and lab utensils
Polypropylene Pyrex® or Type I borosilicate glassware
Vacuum (pre and post) are appropriate for sterilizing large or porous items:
Media solutions in appropriate containers, such as tissue culture flasks with loose caps for a steam autoclave cycle
Pipette tips and other high-density polyethylene products, such as syringes
Wrapped dry items that can trap air
Animal cages and bedding
Choosing an Autoclave
Choosing the right autoclave for your purposes requires you to not only assess the type of media to autoclave, but also throughput capacity, available lab space, and access to utilities including electricity (with proper power output), water and house steam.
Due to the simplicity of the gravity-displacement mechanism, which requires an autoclaving chamber, a heating mechanism, intake and exhaust valves, there is great flexibility in design for gravity autoclaves, including front and top-loading types.
The top-loading type autoclave is particularly advantageous, as it allows for maximum loading space, minimum floor space requirement and does not require a any building steam connection, as the vertical chamber design allows for water to rest at the bottom, which in turn is turned into steam through a heating element located at the bottom. Note that many autoclaves on the market, especially compact top-loading autoclaves often require no more than access to the proper electrical outlet type and enough space to place your autoclave.
Gravity autoclaves are also particularly advantageous when used in geographical areas of high humidity or higher altitudes as they consistently retain the relationship between pressure and heat within the autoclave chamber and overcome differences in boiling points at higher altitudes by opening and closing the exhaust valve. Known as high altitude autoclaves, their functions allow for proper sterilization to occur in laboratories and hospitals located in markets with high altitude terrains.
Regarding the size of your autoclave, in order to limit energy use and costs especially for smaller labs, it is important to buy the proper size autoclave that will accommodate the equipment that needs sterilizing, while not going over capacity. For this there are several autoclaves that range between 50 L and 70 L, which tend to strike a good balance between relatively high capacity and low energy use.
Autoclave sterilizers are essential for almost any type of laboratory. It is crucial to choose the autoclave that suits your needs. Autoclaves come in many shapes and sizes, it can be overwhelming to make the right selection. And stressful wondering whether you have made the correct decision. Choosing the right autoclave depends on several factors. To assist you in your autoclave search, we have outlined the most significant factors that will help you choose the right autoclave for your sterilizing needs.
Type of Sterilization Media
Autoclaves function through either gravity or vacuum-induced or pre-vacuum (prevac) sterilization methods, though some types of autoclaves combine both methods to sterilize.
For the most commonly used types of sterilization media, including glassware, utensils and non-porous items, gravity displacement steam autoclaves are used. Whereas for large and non-porous items such as blankets and other media, vacuum type sterilizers are recommended.
One of the most important things to check is that the autoclave is large enough to fit the largest items that you will be autoclaving. Autoclave size is often measured in Liters. A unit that measures the total volume of the inside of the chamber, yet, the effective chamber size is usually smaller than the actual chamber size.
Not only is the capacity of the chamber important, but one must consider the configuration of the autoclave chamber to determine whether the autoclave will meet your size needs.
Most laboratories and start-ups do not need a huge autoclave. Especially one that requires a large amount of space, plumbing, electricity and house steam. Not to mention significant monetary and time investments for installation, maintenance, and opportunity costs when an autoclave requiring a large amount of technical expertise breaks down.
Second, the throughput capacity will determine whether your autoclave is suitable for the amount of autoclaving media that must be sterilized on a daily basis. To determine an autoclave’s throughput, the amount of autoclaving media that can be sterilized per cycle (as well as the amount of time needed to prepare, load, and unload media) would determine whether a given autoclave would meet your daily sterilization needs.
Autoclaves have different warm-up and cool down times that can add to the cycle time. Certain features, such as cooling fans can speed up this process, in some cases allowing for more cycles in a day and a higher throughput.
Autoclave and Benchtop Space
You should assess the space that you have available in deciding what type of autoclave to buy. Autoclaves come in many shapes and sizes, which have advantages and disadvantages.
The following reasons lead to significant waste for front-loading autoclaves:
Inside the box/outside the chamber. To start, autoclave chambers are cylindrical due to physics, which need equal pressure throughout the chamber. Horizontal autoclaves are sideways facing cylinders enclosed by a box. With this design, the spaces around the outside of the chamber within the box gets wasted.
Within the chamber. Items must have a flat surface on which to rest, accommodated by using trays that slide into the chamber. With this system, the areas outside of the flat surface inside the cylindrical chambers are wasted.
On the tray. Autoclave media, especially glassware tends to be round in shape, including flasks, bottles, petri dishes, etc. When placing round objects on a rectangular area, the areas along the edges are also lost, as round objects only come in contact with the edge of a tray at one small point. The rest is lost space.
Basic lesson- circles and squares do not mix. This principle works the same with autoclaves.
So, top-loading autoclaves are much more efficient in their use of space. The vertical configuration of top-loading autoclaves and stackable baskets allow for the most efficient use of the vertical cylindrical chamber. Combined with the round-shaped sides, top-loading autoclaves can accommodate large capacities of autoclave media, which tend to have round edges.
Installation Utilities: Water and Electricity
Access to water is an important factor, as some autoclaves need plumbing. Others can function by adding water to the unit. But, not all water is equal when it comes to steam sterilization. Much of the tap water in the Unites States contains a high mineral content, including lime, which can calcify and leave residue on the autoclave’s heater and within the chamber. This will cause irreversible damage, especially to the heating unit, which is central to autoclave’s function. You can check the mineral content (hardness/alkalinity) of the water in your area here. To avoid these issues, de-ionized (DI), or de-mineralized, water should be purchased or created by de-ionizing tap water using special equipment found in most laboratories. It is important to stress that this is not the same as distilled water, which only removes ionic impurities but does not change the mineral content.
Autoclaves also have different voltage requirements so your electricity source is another factor to consider. Some may need 220-240V (different to standard 120V outlets), which has the advantage of a faster heating time. Changing voltage requirements can usually be performed by a qualified electrician for a small fee.
Maintenance, Cleaning and Technical Support
As mentioned, autoclaves need regular maintenance for safety, proper functionality and minimal negative impact on your organization’s operation. But, if there is an issue with your autoclave’s operation, you should also ensure you have a reliable and quality technical support available. Purchasing from a large distributor could leave you on a waiting list and could also mean you have to deal with expensive technicians, though certain manufacturers do provide quality technical support that could also be free of charge.
One major aspect that should be considered when purchasing autoclaves is the chamber lid gasket, which differ in quality, longevity (frequency of changing) and price. Because of the intense heat and pressure that gaskets are subjected to, the gasket’s design and material quality is directly correlated with the frequency of which it must be changed.
Summary (The Bottom Line)
When choosing an autoclave, it is important to assess a variety of factors to make sure that the autoclave meets your organization’s needs. Including the autoclave’s capacity, throughput, space requirements, installation, maintenance, quality and costs over several years. Always make sure to consider not only factors such as selling prices, but long-term costs associated with the capacity / throughput, performance, and reliability that affect any organization’s bottom line.