Technical Articles

5 factors affecting your fume hood performance

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Research is a serious work and fume hood is a very important piece of this work. Often times, scientist/ project managers tell us, that their labs are very safe to work, because they think:-

  1. They have one of the finest branded fume hoods for their labs.
  2. All fume hoods have expected face velocity at safe opening height.

However above 2 conditions does not mean that your labs are safe for researchers. Fume hood without its exhaust system is just a box. Its performance depends on many internal and external factors. It is observed that around 15-30% fume hoods fail to pass ASHRAE 110: 2016 site performance tests. Let that be any brand then!

You need to be aware of several equally important factors which directly impact fume hood performance and user safety. I have captured all those 5 important factors in descending order:-

    1. Fume hood design:

      Fume hood is meant for smooth exhaust of the flow without any reverse flow towards the user. Hence, it is imperative that the fume hood design has to be very aerodynamic: i.e. the airfoil has a right aerodynamic shape to allow proper airflow below/above it; when the sash is fully closed. The sash handle should be aerodynamic to avoid eddy currents, baffle arrangement should facilitate immediate fume hood exhaust, exhaust port should have right size, corner posts should be aerodynamic, and the bypass arrangement of the fume hood should have right design. Each and every element mentioned above contributes a lot towards a safe fume hood design.

      An incorrect design of fume hood is a disaster in waiting!

    2. Supply air:

      Lab supply air should be lesser than exhaust air to keep labs under negative pressure. Otherwise, it will impact fume hood performance too.
      Also, supply air diffusers should be at least 5 feet (1.5 meter) away from fume hood sash plane. One should choose low velocity diffusers to avoid any turbulence in the fume hood flow. Draft of supply air should not be directed on the face of fume hood. This directly impacts the fume hood flow and the fume leakages can increase.

      Also ensure that cross drafts within the room are below 30 fpm (0.15 m/s). There should not be any ceiling fan near the fume hood. It will affect the air entering the fume hood causing leakages.

    3. Exhaust system:

      If fume hood is a body, then exhaust blower is a heart and ductwork is like blood veins. A right sizing of blower & ductwork is very important for smooth flow. Blower capacity determines the fume hood face velocity. One small change in the position of dampers (fume hood dampers, branch dampers, bypass dampers) installed in the ductwork can impact the fume hood flow.

      A Variable Air Volume system has many electromechanical components. Our experience shows that due to heavy wear & tear; VAV components start failing in 3 to 5 years. This might go un-noticed, in case if you do not have robust maintenance program.

    4. Exhaust stack design:

      A bad exhaust stack design will not only spread the fumes in the surrounding areas, but it will also bring back the chemical fumes back to your lab. Many labs in densely populated areas suffer from this problem today.

      It is important to use a high height stack (as per local pollution control board rules). A safe bet will be to keep it at least 10 feet (3 meter) above the roof level of the building. Also, never place a supply AHU in the close vicinity of the exhaust stack. These might short circuit the air and bring back the chemical fumes to your lab.

    5. User work practices:

      This is one of the most important factors affecting a fume hood performance and user safety. Some common incorrect practices which affect fume hood airflow:-

      • Lab equipment loading inside the hood; blocking its airfoil and baffles.
      • Keeping sash open often above safe opening height
      • Putting head inside the hood
      • Ignoring the airflow alarm for low/high flow.

      Any of the above actions will leak fail the very purpose of the hood and will expose the user directly to the fumes.

      Even if you get the best fume hood in the world and design the best exhaust and lab supply air systems; you can’t protect people who follow incorrect and unsafe work practices.

These are the 5 topmost important factors which directly affect the performance of your fume hoods. So if think you need guidance to select a complete and good fume hood-exhaust system or if you want to evaluate the performance of your existing fume hoods; please feel free to write to us at:

Portable COVID19 Testing Lab

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Currently India is experiencing the COVID-19 pandemic. The entire country is vulnerable and the statistics of infected and affected people is growing day by day. As on 27.3.2020; we have capacity to test only 15000 samples/ day all over India and we will need many more test facilities in rural India too, practically in every district.

Hence, Sciencebydesign Labsystems Pvt Ltd (Turnkey lab construction company), Arena Consultants (Lab Architects), & Firstsource Laboratory Solutions (Lab equipment company) have come together to design and develop a Portable Container Test Lab setup for testing COVID-19 virus. It is our sincere attempt of setting up such facilities for the benefit of our fellow countrymen.

  • This is a PORTABLE / MOBILE/ CONTAINER Lab setup for testing COVID19
  • Lab set-up will be done in Container of size- 20’-0” x 8’-0” and can be transported to any location in India
  • Lab design is done considering CDC guidelines, GMPP (Good microbiological practice and procedure)and WHO Guidelines
  • It will have the capacity to carry out testing for 250 to 300 samples per day in 12 hours
  • Sample collection will primarily be from hospitals and it is assumed that they are delivered to this centre in batches
  • It is considered that the testing will be done via government approved ‘KITS’ only

Features :

  • The lab layout is compartmentalized in 3 sections:-
    1. Sample receiving area and storage
    2. Testing area
    3. Discard area
  • The lab is designed as a negative pressure lab with UNI-DIRECTIONAL FLOW from entry to discard point and will have the provision of AHU with fresh air supply. The entry will be through air lock.
  • Container has been furnished with storage for all PPE’s at the entry point and with under counter storages for reagents etc, inside the lab.
  • Lab has space planning all necessary equipments: Fridge (4 Deg C), frost free freezer (-20 Deg C), centrifuges 4 Deg, vortex mixer, certified class II BSC Type A2, real time PCR with work station, autoclave, sink with eye-wash, computer and A4 size printer
  • Discard area is segregated from main lab and all waste will be treated as bio-hazard waste as per PCB guidelines.


View 1

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Note :

  • All the lab equipment and mechanical equipment are one-time set-up that will be provided in this.
  • Exclusions: Trained medical staff to run the facility, PPEs, consumables, Testing Kits do not form the part of this portable unit.

For inquiries: Salil Sansare @

Why your high-quality lab furniture & fume hoods are corroding? (Part 2)

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Are we using the fumehoods & lab furniture correctly or the way they should be used?

Taking it ahead from my previous blog on corrosion in fume hoods, in most cases, I typically observe unhealthy and unsafe practices of lab users.

It is a very common practice is to keep the fume hood sash open or above the safe opening height marked on the hood. In such a case, the primary function of fume hood- containment is totally lost.

I also observe that corrosive chemicals are stored in general storage or flammable solvent storage cabinets. For corrosive chemicals, one should use special cabinets which are chemical resistant and ventilated. Yellow coloured flammable solvent storage cabinets are not meant for corrosive chemicals storage.

I strongly think that good housekeeping practices are a must and have to be brought in as a policy in all labs. The chemical spills on fume hood airfoils or lab furniture are not immediately cleaned. Now, if these metal components are not wiped immediately, then it is obvious that few chemicals will attack the metal & eventually lead to corrosion.

This casual approach does not work in the lab. It is a great risk and causes lasting damage to lab infrastructure. The scientists who would treat the lab furniture like their own kitchen and inculcate safe working practices will definitely experience that it lasts much longer and labs are much safer.

Why your high-quality lab furniture & fume hoods are corroding? (Part 1)

By Technical Articles No Comments

In my visit to a few old chemical or pharma research labs, I found that the furniture and fume hoods are corroded. When this was discussed with users & engineering team, almost all of them pointed out towards the poor quality of lab furniture. Whether Indian or imported, premium or standard brand, the quality matter is always in question.

However, very few try to dig deeper. There are many possible reasons, the manufacturer’s quality being only one of those. We will try to understand a few main reasons for this corrosion.

 Reason 1: ‘Poor ventilation design’

Chemical labs must be under negative pressure. Many labs do not have a proper balance of supply and exhaust air. It can be because of improper fume hood exhaust volume calculations, wrong diversity factor, improper VAV system commissioning. Sometimes, the return air system is used in the chemistry labs, heat recovery wheels are installed for hoods or VAV controls have a very slow response time. This all leads to the accumulation of chemical fumes in labs, which attack the metal.

A few years back while commissioning of a research lab with nearly 100 hoods, we found that most labs are designed to be under positive pressure. When we raised this issue with Project Manager & HVAC vendor, they tried to justify their design. When we tried to explain the codes and practices, the vendor never agreed. He insisted that labs must always to be kept under positive pressure. In fact, he has been doing this for the last 30 years. He was a long time vendor for the client and had executed HVAC piece for their several R&D labs. No wonder, their all old labs had serious contamination issues.

Now in such cases, if labs are under positive pressure, rest assured that your all lab furniture and equipment will eventually corrode. It is just a matter of time. If this fume exposure can corrode the metal; one can simply imagine how unsafe it is for a researcher.

Say no to unsafe labs!

#labdesign #fumehood #labfurniture #labsafety #saynotounsafelabs

Read this guide for your Lab Furniture planning to ensure safety in your Laboratory

19 point guide to Laboratory FURNITURE planning – Indian context

By Technical Articles 3 Comments

1.     Nature of the facility and the objective of building it:

The pharmaceutical research facility will need a lot of wet labs; but a clinical research facility will need more of analytical laboratories with lot of support area. Hence, the furniture height and utility requirements will change significantly, depending on the requirements. As such the intent of building the facility has to be drawn first.

2.     User habits:

User habits play a major role in selection and planning. For example, in a university lab, students tend to store chemicals in the fume hoods and lab furniture; hence it is important to have more chemical storage cabinets below the hoods or furniture. Whereas, in regular research labs, there are designated chemical storage areas and chemicals are usually not stored in lab furniture. Hence, lab furniture planning and material of construction for both labs may be different.

3.     Need of flexibility:

A lot of new age research labs need flexibility for future expansion. For such labs; you can look at flexible laboratory furniture options available with most manufacturers. Furniture on castors, ductless fume hoods, ceiling suspended flexible ceiling are such concepts which can help you build flexible labs with ease of re-installation.

4.     Capacity and work flows:

Depending on how many researchers will occupy the laboratory; the workup space, fume hoods and seating spaces need to be finalized. Depending on the workflow and work type, walk-in hood, distillation hood or bench-top hoods are selected. Researchers seating and working areas should not be very far.

5.     Furniture configuration:

You have many options to choose from: fixed plinth based system, flexible C frame, H frame and castor systems too. Depending on the future expansion plans, a right type of furniture configuration should be opted.

6.     Steel or Wood:

Depending on the usage, comfort level of users & user company’s internal standards; the material of construction is decided. Powder coated steel or engineered wood are two main options available today. Each option has its own pros & cons; which had to be weighed before taking a final call.

Further the furniture should be clutter free and ergonomic in design. Cluttered design makes cleaning difficult and adversely impacts material and man movement, creating serious safety implications. For example, movement space between two tables should be 1.5 meters at least. Also, wet lab’s furniture should have standing height (900 mm) and instrument lab’s furniture should have seating height tables (750 mm) with adequate leg spaces.

7.     Worktop finishes:

Every lab will have different needs. Granite is most commonly used; but now there are several other options like: Ceramics, phenolic laminates, epoxy tops etc. Biotech laboratory will need worktops which are resistant to microbial growth, whereas a chemical research lab will need a worktop which withstands a lot of aggressive chemicals. So, take the samples from the furniture vendors and test those before making final decision.

8.     Chemical storage strategies:

Depending on the type of chemicals, you can decide whether to use corrosive chemical cabinets or flammable solvent storage cabinets. Corrosive cabinets have chemical resistant coatings whereas flammable storage cabinets have capacity sustain fire for some time. Even in flammable storage cabinets; you have options of FM approved cabinets or 30-90 minutes fire rated cabinets. You need to plan for ventilation of these cabinets too.

9.     Extraction systems:

Extraction systems although do not fall directly into furniture category, yet they are part of furniture infrastructure. You don’t need expensive fume hood to extract fumes everywhere. You can use canopies on wash areas, spot extractors over rotavapours or enclosures over analytical balances. This will help you reduce exhaust volume and also will cut the cost.

10. Pollution control options:

Depending on the type and volume of chemicals, you can decide to opt of either wet scrubbers or dry scrubbers. Also, the exhaust stack must be sized in such a way that fumes do not re-enter the facility. Please check your local pollution control board norm before finalizing this.

11. Compliance with user’s suitable standards:

Depending on the customer’s requirement of international standard; the lab furniture type will vary. If the customer is a North American company; they will prefer buying hoods which complies to ASHRAE 110: 2016 standard. But if it’s a European company, they may want to look at EN 14175: 2003 standard and stick to fume hood performing according to those standards. Same logic applies to lab furniture too

12. Compliance to safety guidelines:

Safety is the most important aspect in lab design. It is important to take note at the time of detailing, that the furniture edges are rounded and not sharp. The furniture accessories such reagent racks, eye-wash, safety showers etc are placed at ergonomically correct locations to avoid accidents at the time of usage. In case of fire-prone reactions, you should review and check adequate fire protection arrangements have been made within fume hoods.

13. Maintenance:

Lab furniture does not really need much maintenance; but fume hood & exhaust system does. Typical hood related maintenance problems revolve around blower’s breakdown, sash ropes breakage and airflow drop. A right fume hood should have countermeasures or ease of maintenance for all this.

14. Availability of spare parts and durability:

Ensure that the makes of spares & accessories are indeed reputed brands. A lot of not-so-good quality brands are used and those fail often. Also, another good idea will be to include 2 years spares as a part of the contract. A check upon durability is important from the investment and safety point of view.

15. Vendor selection and after sales service:

There is no point to decide about the vendor purely on the basis of the brochures.

The decision to buy from a particular vendor should be made after visiting some of their old installations and ascertaining their capabilities. The vendor’s compliance to global standards with third party test certificates should also be considered.

It is essential to check whether the company has an authorized local partner/service center in close vicinity to ensure minimum down time.

16. Involvement of all stakeholders:

Users, Project engineers and Architects must be involved for this decision. Otherwise you may expect a lot of re-work and dissatisfaction.

17. Budget:

Depending on the specifications and manufacturer; the prices will vary. For example, one simple 6 feet fume hood can be available in the range of Rs. 1.5 lacs to Rs. 4 lacs. So budgeting is really important. Price difference between imported furniture & Indian furniture can be very significant. If you are an export duty exempt unit; then imported furniture may be a good option for you.

18. The ROI:

Factor in the ROI. A marginally higher investment in VAV fume hoods can save a lot of running cost by cutting down exhaust of conditioned air, blower and AHU sizing. The payback period of such system is typically 18-24 months. Or consider buying a state of the art design style in lab furniture, which will stay relevant for next 20-25 years.

19. Last but not the least-Aesthetics:

One of the most important part and it goes without saying that everybody wants a very good looking lab. Colours play a vital role here. So, choose colors wisely. If you use common colours, don’t expect your lab to look uncommon.

Read this before thinking about getting a turnkey service for your lab setup

Should you opt for turnkey lab setup (Design & Build) services?

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When you decide to build a research lab, there are many activities you have to deal with. Lab design, civil interiors, HVAC, electrical, fire alarm systems, plumbing, drain, gas piping, data, CCTV, office furniture, lab furniture, pollution control systems etc. It is a herculean task! You are actually trying to deal with at least 13 vendors at a time to get the job done with right quality & speed. If you involve too many vendors; there are 90% chances that the result will be a combination of delay & poor workmanship.

Turnkey lab setup approach works well, when you are setting up a lab from 1000 sq feet to 20,000 sq feet and you have time pressure or your engineering team’s bandwidth is not available for this project.

A single, specialized & experienced vendor can take up the whole work and complete it on time and with good quality. He knows the nitty-gritty of the lab design standards, safety requirements and can translate your requirements into the exacting lab specifications. He is your one point contact for everything in lab project and all you need to do is -review his progress periodically and give him quick decisions.

This frees up a lot of time for you to order your precious lab equipment, recruit right staff and focus on your routine research activities. Not only you will complete the project on time, but it will also help you save a lot of cost overruns. Turnkey execution will be immensely useful approach, if you select a right vendor.

Chemical Fume extraction strategy for making lab safe

6 fume extraction strategies for a research lab

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In a research laboratory, you may need fume extraction systems to take care of chemical fumes. Every time, you need not install a fume hood, which consumes a lot of space and is also an energy hogging equipment. You have many options available. Depending on the type of reactions and safety protocols; you can decide which system can be most suitable.

This article briefly covers few options with its pros and cons.

1)   Ducted Fume hoods:

Fume hoods are typically used for heavy fume generating reactions. These are fully featured enclosures which have various utilities and flow controls. It is a very important piece for user safety; but an expensive equipment in terms of running cost.

Standards:                ASHRAE 110-2016, EN 14175:2003

Exhaust :                   450-1050 cfm; depending on hood size.

Types:                       a lot of variety of sizes and options.


  • Fume are completely removed from the workplace
  • Low maintenance,
  • Energy efficient if clubbed and used with VAV.


  • Fixed and steady assembly as ductwork is involved.
  • Less energy efficient in single use.

2)   Ductless Fume hoods:

New generation of fume hoods; which have activated carbon filters to remove chemicals from fumes and re-circulate the cleaner air in the laboratory. These are available with most features of a regular fume hoods; and have several variants.

Standards:                AFNOR NF X 15-211:2009, BS 7989: 2001, ASHRAE 110-2016

Exhaust:                    450-1050 cfm; depending on hood size; but this air is re-circulated.

Types:                      Llimited variety of sizes and options.


  • Ducting work eliminated,
  • Simple plug and play mobile unit,
  • 70% less running cost as compared to conventional fume hoods,
  • Cheaper & faster installation


  • Filter maintenance and disposal required,
  • Limited application with carbon filter,
  • Risk to chemical exposure while upon filter loading.

3)   Enclosures:

These are small volume, no frills fume hoods with only 4 walls and exhaust arrangement. The four walls are made up of glass or acrylic/poly carbonate for full visibility. Enclosures won’t have any socket or tap. It only kept over a fume generating equipment and a small exhaust arrangement is made. This ensures that the fumes will be contained and exhausted, rather than spreading in the lab.

Exhaust volume :     200-600 cfm; depending on hood size.

Types:                       Built to suit.


  • Better than spot extractors and canopy hoods.
  • Easy access from front.
  • Cable entry port is available.


  • Not meant for heavy chemical reactions.
  • More suitable for instrument labs.

4)   Mobile extraction units:

A mobile suction and filtered equipped unit used for dust, fume and steam extraction which can be moved quickly wherever needed. The dust is then stored in the bag. In case of fumes, those are filtered through a carbon filter and re-circulated. This machine can be used like a portable vacuum cleaner.

Exhaust volume :     100-200 cfm

Types:                       only 2-3 models available


  • Small, Mobile suction and filter system,
  • Low noise, excellent ergonomics and handling.
  • No ductwork and blower installation required.


  • Can be used for small localized reactions only.
  • Suitable for labs where ductwork is not possible.

5)   Canopy Hoods

A fixed wall mounted or ceiling suspended exhaust fume extractors unit usually placed above the sink to extract acidic fume as generated by waste acids. Also, most popularly used above ovens or other steam generating equipment’s to extract their heat or steam generated. Made up of polypropylene or Stainless steel.

Exhaust volume :     600-900 cfm depending on hood size

Types:                       can be totally customized, built to suit.


  • Suitable for hot-air steam extraction and for waste acid thrown in the sink.


  • Considerably more space required (min-6 sq.ft.)
  • The contaminants directly pass the users breathing zone.

6)   Spot Extractors

A localized chemical resistance fume extraction mechanical arm used to maintain a clean working environment with a volume handling capacity of 100 cfm. Available in PP or aluminum.

Exhaust volume :     100-200 cfm depending on the type.

Types:                        Limited variety of sizes and options.

Advantages:             Highly suitable for localized reactions (rotavapors etc)

Limitations:              Limited working radius, max up to 6 feet.