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Working After Hours or Alone Guideline


This policy applies to all laboratories in the Faculty of Engineering and Natural Sciences.


Laboratory Working Hours are from 8:00 to 17:00 for Monday through Friday. All other times (weekends, holidays, etc.) are regarded as after-hours.

A person is said to be working alone when no one else is in direct line of sight or within sound of that person, at any time, day or night. Working alone is discouraged and prohibited for research purposes, particularly those involving hazardous chemicals and/or experimental procedures.

You should have a proper technical reason to perform laboratory work after hours, i.e. between 17:00 and 8.00. It is inadequate to declare that you need to perform some work which can just as easily be carried out during working hours.

General Principles

If it is necessary to work after hours or alone:

  1. Reconsider the need. Are the increased health and safety risks truly outweighed by the outcome of the experiment?
  2. Reconsider the timing and arrangement of the work. Is there any way to fulfill the required tasks during working hours when others will be present?
  3. If the timing of the task cannot be changed and you still think it must be performed when the laboratory is empty, is there any other person trained in relevant laboratory procedures who can accompany you during your work?
  4. If not, you can find anyone else who could act as a “buddy” to periodically check on you while you work alone. Routine checks can be performed either physically or via a phone.

Working after hours or alone must not be attempted if there is a sensibly conceivable risk that the work might cause a serious accident which would require a second person to be available to summon help.

Working after hours or alone is discouraged under following circumstances:

  • Work with pyrophoric materials
  • Work with highly reactive materials
  • Work with HF
  • Experiments involving large quantities of cryogenic materials
  • Toxic or otherwise hazardous chemicals included experiments
  • Experiments involving high-pressure equipment
  • Experiments involving work with unstable (explosives) materials
  • Work involving entry into a confined space
  • Work around high voltage
  • Experiments involving Class 3 or 4 Lasers
  • Transfer of large quantities of flammable materials, acids, bases, and other hazardous materials
  • Changing compressed gas cylinders containing hazardous materials
  • Work with static sensitive devices
  • Work with moving machinery - lathe, drill
  • Working in cold room

Instances when working after hours or alone is permitted include:

  • Office work
  • Housekeeping activities
  • Assembly or modification of laboratory apparatus. Here, no chemical, electrical, or other physical hazards should be present.
  • Routine lab functions as part of standard operating procedure.


Health and safety risks can increase when working alone during after-hours, due to the unavailability of immediate assistance. If possible, working alone, especially after hours, should be avoided. Lab users planning to work after hours or alone should outline the activities to be performed after hours or alone, and identify hazards, risks, and required control measures. This will help users decide whether the work can be safely performed after-hours.

Working after hours or alone requires Principal Investigator (PI) approval. Approval form is completed online by the individuals who intend to work after hours or alone and submitted to PI for approval. Principal Investigator is Thesis Advisor for graduate students and Responsible Faculty Member of the project for undergraduate students.

Online form can be accessed from here.

The Principal Investigator has the responsibility to ensure the safety of all lab users in their laboratory. Principal Investigator can approve laboratory users to work after hours or alone, upon conducting a hazard review. The review should be verbally conveyed to affected individuals. Once this review is completed for a certain procedure, it does not need to be repeated for subsequent similar procedures. After-hours or working alone approval should be reviewed if there is a change in the workplace or procedures to be carried out.

If the PI determines that the risks associated with the experiment cannot be minimized to a controllable level, then the lab user should perform his/her work only when other users are present.


Freshmen and sophomore-year students and visitors (including interns, researchers etc.) are never permitted to work after hours or alone in a research laboratory. They must always be accompanied by an eligible lab user (Undergrad/Grad/Post-Doc/PI). For junior and senior year undergraduates, approval is needed to work after hours or alone in the lab. In addition to PI approval, supervision is needed (buddy is recommended) for working after hours. Graduate Students and Postdoctoral Researchers should have approval from their PI to work after hours or alone in a research laboratory. Working after hours is not allowed for visitors (Figure 1).

Figure 1. Working after hours or alone
 Pre-requisiteWorking Alone or After Hours
1st and 2nd year
All should take 
General Lab Safety 
Training before 
getting lab access
No working alone during day time or after hours
3rd and 4th year
PI approval + Lab experiencePI approval + Supervised by an eligible user 
Graduate and
PI approval
VisitorNo working alone during day time or after hours

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