Calculating Pressure Drops Across Valves

Calculating pressure drops can be very helpful in identifying more accurate pressure profiles during a Process Hazard Analysis (PHA) / Hazard and Operability Study (HAZOP). There are scenarios during a PHA/HAZOP where taking a conservative estimate ends up overstating the severity of a potential incident significantly. 

Facilitators and team members need to remember that taking credit for the laws of physics is allowed and can be significantly more accurate. In cases such as blowthrough due to level valves going wide open, teams should analyze pressure drops across valves. This allows for a more realistic analysis of what pressure the downstream vessel can reach. This calculation is not difficult if valve information is readily available. In this TechTip, we will provide a simplified discussion on pressure drops and how to calculate pressure drops across valves. 

Michael Pfaff, Project Engineer- published 12/17/2021

TechTip Link

Maximum Intended Inventory

The maximum intended inventory, as the name suggests, is the maximum amount of the regulated substance or chemical in a covered process, which the facility plans to store onsite. Facilities with a covered process typically will have various pressure vessels, storage tanks, heat exchangers, pipelines, etc., all of which contribute to the overall quantity of material. This Tech-Tip aims to briefly introduce the process safety information requirement listed under Occupational Safety Health Administration Process Safety Management / Environmental Protection Agency Risk Management Plan and California Accident Release Prevention programs. 

Oscar Hernandez, Project Engineer- published 8/27/2021

TechTip Link


Quantifying Thermal Expansion

Thermal expansion is the increase in volume of a fluid as the fluid is heated (e.g., due to solar radiation, steam tracing, external fire, etc.). In the case of a blocked-in liquid-full system, this gradual expansion of the fluid can cause extreme build-ups in pressure. While most people are vaguely aware of the potential for thermal expansion; they may not understand the physics behind it. This Tech-Tip aims to briefly introduce the governing principles of thermal expansion as well as an equation to calculate the change in pressure. 

Craig Stickelmaier, Project Engineer- published 7/7/2021

TechTip Link

Efficient and Effective Incident Investigations

Ammonia, a versatile toxic compound, is one of the most widely used refrigerants, and is one of the world’s most produced chemicals. Despite using inherently safer design philosophy and conducting risk assessments, problems and failures leading to releases of this toxic substance still occur frequently. 

James De Graw, Project Engineer- published 6/3/2021

TechTip Link

CalARP Program 4 - Hierachy of Control Analysis (HCA)

California’s CalARP Program 4 requires Hazard Control Analysis (HCA) be performed to aid in hazard prevention. This article serves as a starting point for understanding how to implement HCA within an overall safety management system. 

Katya Mandziuk, Project Engineer- published 5/21/2021

TechTip Link

Bypassing EPA RMP Submittal Snags

Misunderstood EPA RMP Submittal elements, explained! Do not worry, you are not alone. Confusion surrounding the data to be input into the EPA RMP Submittal is all too common, which leads to inaccurate details and errors in the submittal process. Some reporting fields within the submittal are not self-explanatory and require further investigation, which takes time and effort to understand.

Bailey Klepacki, Project Engineer – published 5/6/2021 

TechTip Link

A Case for Natural Refrigerants: An Environmental Point-Of-View

How does a natural refrigerant compare to synthetic refrigerants? As the United States prohibits the use of some synthetic refrigerants, the industrial refrigeration industry will encounter challenges in choosing the correct refrigerant. This TechTip discusses some some of the evidence to consider when making this evaluation.

Stephanie Smith, PE, Senior Engineer – published 9/30/2020 

TechTip Link

CalARP Program 4 - Management of Organizational Change (MOOC) Requirements

Is your facility considering making an organizational change?
If so, you may need to consider whether or not you should complete a Management of Organizational Change (MOOC). MOOC assessments are a useful tool for any facility considering restructuring their management systems and can help make sure the transition to a new management system goes smoothly. 

Carine Black, Senior Engineer – published 9/16/2020

TechTip Link

EPA General Duty Clause for Ammonia Refrigeration Industry

A new EPA compliance initiative will enforce “Process Safety-esque” requirements for low-threshold ammonia refrigeration facilities nationwide. Learn how the General Duty Clause initiative will exact compliance to reduce risks to human health and the environment.

Ryan Bray, Technical Consultant – published 8/31/2020

TechTip Link

EPA Risk Management Program (RMP) Reconsideration Final Rule - 40 CFR 68​

How do I ensure my RMP-regulated facility stays compliant? The EPA’s RMP Reconsideration Final Rule (FR) solidified the importance of existing 40 CFR 68 regulations related to emergency planning and availability of public information. Much has not changed regarding these rules which remain intact; however, the assignment of new compliance dates is worth noting. This TechTip will go more in depth of the final ruling.

Kayla Cervera, Project Engineer – published 8/18/2020

TechTip Link

Storage and Handling of Anhydrous Ammonia - CFR 1910.111

Does your facility store anhydrous ammonia onsite? If you do, you are probably aware of the PSM/RMP regulatory requirements associated with exceeding EPA/OSHA thresholds. If you are under the PSM/RMP thresholds, you may think that you are in the clear of any federal regulatory obligations. But you are familiar with the OSHA CFR 1910.111 requirement for “Storage and handling of anhydrous ammonia”? Regardless of the federal thresholds listed for PSM applicability, OSHA has established additional requirements for the storage and handling of anhydrous ammonia that you should be aware of. In this Tech tip, we will discuss these requirements and what they mean for you. 

Michael Pfaff, Project Engineer – published 7/31/2020

TechTip Link

Calculating Maximum Blocked In Discharge Pressure

“What is the maximum blocked in discharge pressure of the pump?” You are probably familiar with this question if you have ever participated in a PHA / HAZOP. Normally, the engineer is responsible for providing the answer to this question whenever the PHA scenario arises in which the discharge path from a centrifugal pump is blocked. Although the question seems simple at first glance, oftentimes, there is confusion about what the term means and how to accurately calculate this for a given HAZOP scenario. In this Tech Tip, we will provide a simplified discussion of how to calculate maximum blocked in discharge pressure for a centrifugal pump. 

Jasmin Dhaliwal, Senior Engineer – published 7/15/2020

TechTip Link