To continue with my series of LOTO articles this month, I want to discuss how 1910.147 plays into our efforts to SAFELY enter a Permit-Required Confined Space (PRCS).  Way too many PRCS entry permits have the basic check-the-box statement "All energy sources isolated - YES/NO".  What the heck is that suppose to meet?  Do our "machine specific LOTO procedures" have the statement "All energy sources isolated - YES/NO" or do machine-specific procedures contain the energy types, their magnitudes, their means/methods used to isolate each source and the means to verify each source is at a zero-energy state (ZES)?  So why in the heck would we think our energy isolation plan for entry into a PRCS can be something less?  So what should our energy isolation plan look like for our entry into a PRCS...

First, let me state this... we do NOT get an exemption from OSHA on DOCUMENTING our machine/equipment specific procedure for the PRCS we will be entering.  In other words, 1910.147(c)(4)(i) still applies and OSHA's expectation (as well it should be ours) is that the permitting process will include an energy isolation plan for that specific PRCS.  The challenge that scares so many facilities is how to do document this isolation plan, when in fact it is quite easy. 

Here is my "Energy Isolation Plan" worksheet (SAFTENG members can download this as a WORD document) that I began using in 1994 in the chemical industry and it has not changed in all those years!  This document has been audited/inspected by OSHA and safety professionals from all types of industries and never once has it been seen as deficient or lacking in any way and that includes VPP scrutiny back when VPP audits were a bear!

Screen Shot 2018 02 10 at 1.19.13 PM

I should also point out that when it comes to the means/methods allowed for 1910.146(d)(3)(iii) Isolating the permit space are limited to ONLY three (3)!  OSHA states: (emphasis by me)

"Isolation" means the process by which a permit space is removed from service and completely protected against the release of energy and material into the space by such means as: blanking or blinding; misaligning or removing sections of lines, pipes, or ducts; a double block and bleed system; lockout or tagout of all sources of energy; or blocking or disconnecting all mechanical linkages.

OSHA has defined the following:

"Double block and bleed" means the closure of a line, duct, or pipe by closing and locking or tagging two in-line valves and by opening and locking or tagging a drain or vent valve in the line between the two closed valves.

"Blanking or blinding" means the absolute closure of a pipe, line, or duct by the fastening of a solid plate (such as a spectacle blind or a skillet blind) that completely covers the bore and that is capable of withstanding the maximum pressure of the pipe, line, or duct with no leakage beyond the plate.


An employer can use any means/methods to DOCUMENT their energy isolation procedures for the PRCS, but it MUST BE DOCUMENTED in a manner that meets 1910.147(c)(4) and a one-line item on the entry permit stating "All energy sources locked out - YES" will NOT cut it.


Just as an FYI... this is what OSHA has stated in their 2008 LOTO Compliance Directive: (emphasis by me)

Relationship between the Control of hazardous energy (LOTO) standard and the Permit-required confined spaces (PRCS), 29 CFR §1910.146, standard.

The PRCS and the LOTO standards are generic and interrelated standards, and both standards may, depending upon the circumstances, apply to the isolation of hazardous energy for a PRCS. The application of the LOTO standard, with respect to PRCS, is governed by §1910.147(a)(3)(ii), which provides that, when other standards require LOTO, the procedural and training provisions of the LOTO standard shall be used and supplemented to effectively control hazardous energy. Therefore, for any particular PRCS, the question will be whether the 1910.146 standard requires LOTO to isolate hazardous energy. The answer to this question depends on the type(s) of hazardous energy that must be isolated, whether LOTO provides isolation (offering complete employee protection), and whether the §1910.146 requires the use of LOTO.

Pursuant to the §1910.146 standard (including its final rule preamble), electromechanical types of hazards, associated with a PRCS, must be isolated in accordance with the LOTO standard (or guarded in accordance with Machine Guarding, Subpart O, requirements). Failure to follow the procedural and training requirements of the LOTO standard should be cited as §1910.147 violations related to the isolation of electro-mechanical hazards.

The PRCS standard does NOT, however, allow LOTO for FLOWABLE MATERIAL ISOLATION. This is because compliance with §1910.147 does NOT, in all cases, adequately isolate hazards created by materials such as steam, flammable gases, flammable and combustible liquids. In a permit-required confined space, hazards associated with flowable materials will be considered isolated only by the use of the following techniques:

      1. blanking or blinding;
      2. misaligning or removing sections of lines, pipes or duct; and
      3. use of a double block and bleed system.

A double block and bleed isolation system, for example, usually utilizes the closure of two valves, the opening of a bleeder valve, and the application of LOTO devices (offering complete employee protection); whereas an employer can comply with §§ 1910.147(d)(3) and 1910.147(d)(4) of the LOTO standard by simply closing and LOTO of a single valve (which could create atmospheric hazards due to the leakage of a single valve).


See also these articles:

View 's profile on LinkedIn

 LinkedIn Group Button



safteng man copy


2018 Training Calendar


BLR Webinar 

Confincd Space Rcscue - OSHA's Latest Requirements,

Safety & Best Practices, and Common Mistakes to Avoid

3/13/18 from 1:30 to 3 pm ET 

75 minute presentation followed by 15 minute Q&A


Process Safety Training

April 2-6, 2018

2600 N James H McGee Blvd

Dayton, OH 45417

CLICK HERE for more info


Partner Companies


Chill Transparent

kemkey logo




 organdonor website reputation