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Revision Log

Light Sources Directorate Policies and Requirements Manual

Number: LS-ESH-PRM-5.1.0
Date: 08/11/09
Revision: 6
Prepared by: Lori Stiegler
Revised by: Keith Klaus
Approved by: Andrew Ackerman (ESH/Q Manager)

General Requirements

Cryogenic liquids are used extensively throughout the NSLS Complex. These liquids must be handled cautiously as they represent significant hazards ranging from skin damage to asphyxiation. BNL has established standards to minimize the risk of personnel injury and damage to property in the Cryogenics Safety Subject Area. These standards apply to activities at the NSLS and SDL. For further information, please contact any member of the NSLS ESH Staff.

Liquid Nitrogen Fill Stations

The NSLS provides two Liquid Nitrogen (LN2) fill stations for use by experimenters in the West Roll-up Door area.  Large dewars may be filled inside and small, hand-carried dewars may be filled outside.  While the fill systems are easy to use, it is necessary for all users to read the instructions provided and have resident beam line personnel demonstrate the proper techniques during Beam Line Operations and Safety Awareness (BLOSA) training. Dewars being filled at these two stations may never be left unattended.

During Liquid Nitrogen truck delivery noise levels outside the building exceed 85 dBA:

·         Outdoor walk-bys allowed; no stopping

·         No use of the small dewar fill station

·         No exchange of gas cylinders

Personal Protective Equipment


See Attachment 1 for Guidelines. 


Transporting Cryogens


·         “Dry Shippers” are available for transporting cold samples.

·         Dry ice may be transported in well ventilated personal vehicles as it will sublimate much slower than the evaporation rate of the liquid cryogens.  Care is still needed when placing dry ice into a closed volume; keep the volume well-ventilated.  One pound of dry ice will sublimate to 8.2 cubic feet of CO2 gas.

Large and small storage dewars

·         Place a loose fitting cap on small dewars to contain splashes.  Never use threaded caps.

·         Use care to avoid spills.

·         Many dewars are awkward and require special care during transport.

·         Use side handles to transport dewars.  Never move a dewar using only the top ring.

Other Cryogen Safety Issues

·         Care is required for removal of canes and vials from small dewars; use the combination of gloves described in Attachment 1.  Use forceps or tongs so that fingers are not immersed in the liquid nitrogen.

·         Small volumes (<1 liter) of waste liquid Nitrogen are best discarded by allowing an open dewar to slowly warm up without applying any heat and allowing the gaseous nitrogen to disperse to the experiment floor.  Small amounts of waste cryogenic liquid may also be released by filling the bottom of a container (a plastic tub, for instance) with cubes of foam insulation and carefully pouring the cryogen into the container; this will allow the cryogen to evaporate slowly.  Label the container appropriately.  Discard larger liquid Nitrogen volumes or any amount of liquid Helium through the Enhanced Work Planning process, by contacting a member of the ESH Staff.

·         There are several areas at the NSLS where there is sufficient cryogen use or storage to present potential for an Oxygen Deficiency Hazard (ODH). These areas are monitored, posted, and alarmed.  Should you be in one of these locations when the alarm sounds, leave the affected area immediately and contact the NSLS Control Room at extension 2550.


·         Liquid helium may only be obtained by ordering a dewar through the BNL Gas Cylinder Warehouse using the following telephone number:  631-344-2964. 

·         Dry ice is available for purchase through the Gas Cylinder Warehouse at 631-344-2964.


·         NSLS User training and beam line BLOSA training cover cryogen safety and are adequate to qualify Users to work with cryogens on the experiment floor.

·         Formal documented training for the large dewar fill station is required.

·         Procedures for operation of the small dewar fill station are posted, and must be read and understood by all who work with that equipment.  Demonstration of the fill stations will be done in BLOSA training when applicable.  Help is also available from each beam line Local Contact.

·         Select NSLS and beam line staff are required to complete BNL’s computer-based Cryogen Safety training.

·         A guideline for liquid helium transfer operations, Attachment 2, is included in the BLOSA training for applicable beam lines.

Infrared Detectors (Bolometer)

Use of both non-pumped and pumped infrared detectors, i.e. bolometers, represents a unique set of hazards and, therefore, requires personnel to follow detailed procedures for detector relief valving, preparation, filling, operation, refilling and warm-up.  Guidance is provided below in Attachments 3 and 4.

Attachment 1 – Revised PPE Guidelines for Cryogen Use

Attachment 2 - Guideline for Liquid Helium Transfer

Attachment 3 - NSLS Procedures for Preparing and Operating Infrared Laboratories IR Detectors Using T=4.2K (Non-Pumped Liquid He)

Attachment 4 - NSLS Procedures for Preparing and Operating Infrared Laboratories IR Detectors Using Pumped Liquid He (T<4.2K)

PRM Table of Contents

Document Review Frequency 3 Years

Review signatures on file with master copy of controlled document

Document Number: LS-ESH-PRM-5.1.0

> See NSLS Quality Control Coordinator for original revision and review signatures <

Rev Description Date
0 Original Document 01/20/93
1 Updated to provide links to Web documents 08/10/00
2 Updated Chairman's name and Web links 07/17/03
3 Added Attachments 1 and 2 regarding bolometer usage 01/13/04
4 Corrected web links. Developed sections on Liquid Nitrogen Fill Stations, Transporting Cryogens, Using Cryogens at the Beamlines, Liquid Helium and Dry Ice. Sections on personal protective equipment improved in response to an experimenter injury. 10/16/06
5 Deleted PPE guidance from PRM body and added it as Attachment 1. Clarified training requirements. Added Attachment 2 for Liquid Helium Transfer. Changed bolometer attachments to 3 & 4. 08/08/08
6 Revised Attachment 1
Added training requirement for LN2 fill station.

For information regarding this document contact Lori Stiegler,